Method of manufacturing a photomask

ABSTRACT

After a shade pattern constituted by a resist film formed on a photomask is stripped, a new shade pattern constituted by a resist film is formed on the photomask to reclaim a photomask.

[0001] This application is a Continuation of nonprovisional applicationSer. No. 09/924,769 filed Aug. 9, 2001.

FIELD OF THE INVENTION

[0002] The present invention relates to a method of manufacturing aphotomask, a method of manufacturing photomask blanks, and a techniquefor reclaiming a photomask and, more particularly, to a technique whichis effectively applied to a photolithography technique used inmanufacturing a semiconductor device, a super conductive device, a micromachine, an electronic device, and the like.

BACKGROUND OF THE INVENTION

[0003] For example, in manufacturing a semiconductor device, as a methodof transferring a micropattern onto a semiconductor wafer, aphotolithography technique is used. In the photolithography technique, aprojection aligner is popularly used. A pattern of a photomask (to bereferred to as a mask hereinafter) set in the projection aligner istransferred onto a semiconductor wafer (to be referred to as a waferhereinafter) to form a device pattern.

[0004] A normal mask used in the photolithography technique is producedby processing a shade material such as chromium (Cr) formed on atransparent quartz substrate. More specifically, the normal mask isconstituted such that a shade film made of chromium or the like isformed on a quartz substrate to have a desired shape.

SUMMARY OF THE INVENTION

[0005] In recent years, competition in development for semiconductordevices advances, and a large number of masks are required to acceleratea device debug operation. The necessity of producing masks at a low costbecomes high. Although a very high cost is required for patterndelineation, defect inspection for patterns, and the like inmanufacturing masks, a cost which is not negligible is required for maskblanks (to be referred to as blanks hereinafter). For example, in ani-line having a wavelength of 365 nm, the cost of delineation or defectinspection is low because an object pattern size is large. In this case,the cost of blanks accounts for about 20% of the total cost of producingthe mask. In a mask for a KrF excimer laser having a wavelength of 248nm, since the degree of flatness of a quartz glass (transparent quartzsubstrate) influences pattern delineation accuracy, the degrees offlatness are classified into grades. In high-quality blanks, the degreeof flatness at a submicron level is required. Since the degree offlatness is obtained by polishing, the yield of blanks having a highdegree of flatness is small because a selection method is used. For thisreason, the cost of blanks having a high degree of flatness is high. Ina mask for an ArF excimer laser having a wavelength of 193 nm or a maskfor an F₂ excimer laser having a wavelength of 157 nm, the costs of theblanks increase because manufacturing methods are different from eachother from viewpoints of prevention of a color center or a reduction indefect density. For this reason, in manufacturing masks, the cost ofblanks cannot be neglected, and the cost must be reduced.

[0006] Therefore, masks may be reclaimed to reduce the cost of blanks.More specifically, a wasted mask or a mask which does not passinspection after a shade pattern made of chromium or the like is formedare subjected to a reclaiming process. A mask reclaiming processexamined by the present inventors is as follows, for example. That is, ashade pattern on a major surface of mask blanks made of quartz glass orthe like is removed by wet etching or the like. In this case, a slightstep is formed on the major surface (surface on which the shade patternis formed) of the mask blanks. Glass polishing is performed to removethis step. This polishing grinds the step on the major surface to form asurface having a high degree of flatness. Thereafter, particlesgenerated in this step are removed by cleaning, and particle check isperformed to reclaim blanks.

[0007] However, in the above mask technique, the present inventors foundthe following problems.

[0008] More specifically, when a normal mask is to be reclaimed, thefollowing problems are posed. That is, (1) the polishing step at a highcost is required, (2) the number of times of reclamation is limitedbecause the mask blanks is thinned by polishing as reclamation isrepeated (i.e., blanks are thinned), and (3) the degree of flatness ismeasured again, and the mask is classified by levels because the degreeof flatness of the mask blanks is changed by the polishing step. Thereclamation of masks does not remarkably advantageous with respect toquality and cost.

[0009] The present inventors performed a technical examination from aviewpoint of a mask on the basis of the result of the invention. As aresult, as another engagement to reduce the cost of a mask, for example,a so-called resist mask method for forming a shade film by a resist filmis disclosed in Japanese Patent Laid-Open Publication No. 5-2189307.

[0010] It is an object of the present invention to provide a techniquewhich can reclaim a mask.

[0011] It is another object of the present invention to provide atechnique which can reclaim a mask while keeping the quality of themask.

[0012] The above objects, other objects, and novel characteristicfeatures of the present invention will be apparent from the descriptionand accompanying drawings of this specification.

[0013] The outline of a typical one of the inventions disclosed in thisapplication will be simply described below.

[0014] More specifically, according to one aspect of the presentinvention, a shade pattern constituted by a resist film formed on a maskis stripped, and a new shade pattern constituted by a resist film isformed on the mask to reclaim a mask.

[0015] According to another aspect of the present invention, a shadepattern constituted by a resist film formed in an integrated circuitpattern region of a mask on which a shade pattern made of a metal isformed in a peripheral region is strip, and a new shade patternconstituted by a resist film is formed again in the integrated circuitpattern region of the mask on which the shade pattern made of a metal isformed in the peripheral region to reclaim a mask.

[0016] According to still another aspect of the present invention, ashade pattern constituted by a resist film and formed in a peripheralcircuit pattern region of a mask having a shade pattern formed in anintegrated circuit pattern and made of a metal and a shade patternformed in a peripheral region and made of a metal is stripped, and a newshade pattern constituted by a resist film is formed again in theintegrated circuit pattern region of the mask having the shade patternformed in the integrated circuit pattern region and made of the metaland the shade pattern formed in the peripheral region and made of themetal to reclaim a mask.

[0017] According to still another aspect of the present invention, thestep of forming a shade pattern constituted by a resist film on a maskand the step of stripping the shade pattern constituted by the resistfilm are repeated.

[0018] Still other aspects of the present invention are as follows:

[0019] (1). A method of photomask blanks comprising the steps of:

[0020] (a) patterning and forming a first shade portion constituted by aresist film on a mask substrate to manufacture a photomask;

[0021] (b) performing an exposure process by using the photomask totransfer a desired pattern onto a substrate to be processed; and

[0022] (c) stripping the first shade portion constituted by the resistfilm on the photomask to reclaim photomask blanks constituted by themask substrate.

[0023] (2). A method of manufacturing photomask blanks according to theabove (1), further comprising the step of:

[0024] forming a mask information pattern on the mask substrate.

[0025] (3). A method of manufacturing photomask blanks according to theabove (2), wherein

[0026] the mask information pattern is formed by one or both of a trenchformed in the mask substrate and a shade pattern made of a metal formedon the mask substrate.

[0027] (4). A method of manufacturing a photomask comprising the stepsof:

[0028] (a) preparing a mask substrate having a shade portion made of ametal in a peripheral region around an integrating circuit patternregion;

[0029] (b) patterning and forming a first shade portion constituted by aresist film in the integrating circuit pattern region to manufacture aphotomask on a mask substrate having the shade portion made of themetal;

[0030] (c) performing an exposure process by using the photomask totransfer a desired pattern onto a substrate to be processed; and

[0031] (d) stripping the first shade portion constituted by the resistfilm on the photomask to remanufacture photomask blanks constituted bythe mask substrate having the metal shade portion.

[0032] (5). A method of manufacturing photomask blanks according to theabove (4), wherein

[0033] in the previous step of stripping the first shade portionconstituted by the resist film, a protective film is formed on the shadeportion made of the metal.

[0034] (6). A method of manufacturing photomask blanks according to theabove (4) or (5), wherein

[0035] the shade film made of the metal comprises a refractory metal, anitride of a refractory metal, a silicide of a refractory metal, or alaminate film comprising thereof.

[0036] (7). A method of manufacturing photomask blanks according to theabove (4), (5), or (6), further comprising the step of:

[0037] forming a mask information pattern on the mask substrate.

[0038] (8). A method of manufacturing photomask blanks according to theabove (7), wherein

[0039] the mask information pattern is formed by one or both of a trenchformed in the mask substrate and a light-transmitting pattern formed bypartially removing the second shade portion made of the metal.

[0040] (9). A method of reclaiming a photomask comprising the steps of:

[0041] (a) patterning and forming a first shade portion constituted by aresist film on a mask substrate to manufacture a photomask;

[0042] (b) performing an exposure process by using the photomask totransfer a desired pattern onto a substrate to be processed;

[0043] (c) stripping the first shade portion constituted by the resistfilm; and

[0044] (d) patterning and forming a second shade portion constituted bya resist film on the mask substrate from which the first shade portionconstituted by the resist film is stripped to reclaim the photomask.

[0045] (10). A method of reclaiming a photomask comprising the steps of:

[0046] (a) preparing a mask substrate having a shade portion made of ametal in a peripheral region around an integrating circuit patternregion;

[0047] (b) patterning and forming a first shade portion constituted by aresist film in the integrating circuit pattern region to manufacture aphotomask on a mask substrate having the shade portion made of themetal;

[0048] (c) performing an exposure process by using the photomask totransfer a desired pattern onto a substrate to be processed;

[0049] (d) stripping the first shade portion constituted by the resistfilm on the photomask to remanufacture a mask substrate having the metalshade portion; and

[0050] (e) patterning and forming a second shade portion constituted bya resist film in the integrated circuit pattern on the mask substratehaving the shade portion made of the metal to reclaim a photomask.

[0051] (11). A method of reclaiming a photomask comprising the steps of:

[0052] (a) preparing a mask substrate having a first shade portion madeof a metal formed in an integrated circuit pattern and a second shadeportion made of a metal formed in a peripheral region around theintegrating circuit pattern region;

[0053] (b) patterning and forming a first shade portion constituted by aresist film in the integrating circuit pattern region to manufacture aphotomask on a mask substrate having the first and second shade portionsmade of the metals;

[0054] (c) performing an exposure process by using the photomask totransfer a desired pattern onto a substrate to be processed;

[0055] (d) stripping the first shade portion constituted by the resistfilm on the photomask to remanufacture a mask substrate having the firstand second metal shade portions; and

[0056] (e) patterning and forming a second shade portion constituted bya resist film in the integrated circuit pattern on the mask substratehaving the shade portion made of the metal to reclaim a photomask.

[0057] (12). A method of reclaiming a photomask according to the above(10) or (11), wherein

[0058] in the previous step of stripping the first shade portionconstituted by the resist film, a protective film is formed on the shadeportion made of the metal.

[0059] (13). A method of reclaiming photomask blanks according to theabove (10) or (11), wherein

[0060] the shade portion made of the metal comprises a refractory metal,a nitride of a refractory metal, a silicide of a refractory metal, or alaminate film comprising thereof.

[0061] (14). A method of reclaiming a photomask according to any one ofthe above (9) to (13), further comprising the step of:

[0062] forming a mask information pattern on the mask substrate. (15). Amethod of reclaiming a photomask comprising the steps of:

[0063] (a) causing a mask user which uses a photomask to place an orderwith a blanks supplier for supplying photomask blanks for photomaskblanks;

[0064] (b) causing the mask user to manufacture a photomask having ashade pattern constituted by a resist film in an integrated circuitpattern region by the delivered photomask blanks;

[0065] (c) causing the mask user to perform an exposure process by usingthe photomask; and

[0066] (d) causing the mask user to strip the shade pattern constitutedby the resist film from the photomask subjected to the exposure processand to sell the photomask blanks from which the resist is stripped tothe blanks supplier so as to reclaim the photomask blanks as photomaskblanks which can be used again.

[0067] (16). A method of reclaiming a photomask comprising the steps of:

[0068] (a) causing a mask user which uses a photomask to place an orderwith a blanks supplier for supplying photomask blanks for photomaskblanks;

[0069] (b) causing the mask user to manufacture a photomask having ashade pattern constituted by a resist film in an integrated circuitpattern region by the delivered photomask blanks;

[0070] (c) causing the mask user to perform an exposure process by usingthe photomask; and

[0071] (d) causing the mask user to sell the photomask subjected to theexposure process to the blanks supplier so as to reclaim the photomaskas a photomask which can be used again.

[0072] (17). A method of reclaiming a photomask comprising the steps of:

[0073] (a) causing a photomask maker to place an order with a blankssupplier for supplying photomask blanks for photomask blanks;

[0074] (b) causing the photomask maker to manufacture a photomask havinga shade pattern constituted by a resist film in an integrated circuitpattern region by the delivered photomask blanks;

[0075] (c) causing the photomask maker to sell the photomask to a devicemaker for manufacturing a predetermined device;

[0076] (d) causing a photomask maker to receive a photomask subjected toan exposure process from the device maker; and

[0077] (e) causing a photomask maker to strip the shade patternconstituted by the resist film of the photomask subjected to theexposure process and received from the device maker and to sell thephotomask blanks obtained in this manner to the blanks supplier so as toreclaim the photomask blanks as photomask blanks which can be usedagain.

[0078] (18). A method of reclaiming a photomask comprising the steps of:

[0079] (a) causing a photomask maker to place an order with a blankssupplier for supplying photomask blanks for photomask blanks;

[0080] (b) causing the photomask maker to manufacture a photomask havinga shade pattern constituted by a resist film in an integrated circuitpattern region by the delivered photomask blanks;

[0081] (c) causing the photomask maker to sell the photomask to a devicemaker for manufacturing a predetermined device;

[0082] (d) causing a photomask maker to receive a photomask subjected toan exposure process from the device maker; and

[0083] (e) causing a photomask maker to sell the photomask subjected tothe exposure process and received by the device maker so as to reclaimthe photomask as a photomask which can be used again.

[0084] (19). A method of reclaiming a photomask comprising the steps of:

[0085] (a) causing a blanks supplier for supplying photomask blanks tosell photomask blanks for manufacturing a photomask having a shadepattern constituted by a resist film to a photomask user which uses aphotomask; and

[0086] (b) causing the blanks supplier to recover the photomasksubjected to an exposure process from the photomask user, to strip theshade pattern constituted by the resist film, and to reclaim thephotomask blanks.

[0087] (20). A method of reclaiming a photomask comprising the steps of:

[0088] (a) causing a blanks supplier for supplying photomask blanks tosell photomask blanks for manufacturing a photomask having a shadepattern constituted by a resist film to a photomask maker whichmanufactures a photomask; and

[0089] (b) causing the blanks supplier to recover the photomasksubjected to an exposure process from a photomask user, to strip theshade pattern constituted by the resist film, and to reclaim thephotomask blanks.

[0090] (21). A method of reclaiming a photomask comprising the steps of:

[0091] (a) causing a blanks supplier for supplying photomask blanks tosell photomask blanks for manufacturing a photomask having a shadepattern constituted by a resist film to a photomask maker whichmanufactures a photomask; and

[0092] (b) causing the blanks supplier to recover the photomask fromwhich the shade pattern constituted by the resist film is stripped froma photomask user and to perform cleaning for removing a particle and aprocess of checking a particle and a scratch to reclaim the photomaskblanks.

[0093] (22). A method of reclaiming a photomask comprising the steps of:

[0094] (a) causing a blanks supplier for supplying photomask blanks tosell photomask blanks for manufacturing a photomask having a shadepattern constituted by a resist film to a photomask maker whichmanufactures a photomask; and

[0095] (b) causing the blanks supplier to recover the photomasksubjected to an exposure process from the photomask maker, to strip theshade pattern constituted by the resist film, and to reclaim thephotomask blanks.

[0096] (23). A method of reclaiming a photomask according to any one ofthe above (19) to (22), wherein

[0097] the blanks supplier manages the quality of the photomask blankson the basis of a blanks information pattern formed in the photomaskblanks.

[0098] (24). A method of reclaiming a photomask according to the above(19), wherein

[0099] the blanks supplier changes the transaction price of photomaskblanks recovered from the mask user by the blanks supplier according tothe number of photomask blanks shipped to the mask user.

[0100] (25). A method of reclaiming a photomask according to the above(19), wherein

[0101] the blanks supplier changes the price of photomask blanksaccording to a ratio of the number of photomask blanks recovered fromthe mask user by the blanks supplier to the number of photomask blanksshipped to the mask user.

[0102] (26). A method of reclaiming a photomask according to the above(22), wherein the blanks supplier changes the transaction price ofphotomask blanks recovered from the mask maker by the blanks supplieraccording to the number of photomask blanks shipped to the mask maker.

[0103] (27). A method of reclaiming a photomask according to the above(22), wherein

[0104] the blanks supplier changes the price of photomask blanksaccording to a ratio of the number of photomask blanks recovered fromthe mask maker by the blanks supplier to the number of photomask blanksshipped to the mask maker.

[0105] (28). A method of reclaiming a photomask according to any one ofthe above (19) to (27), wherein

[0106] the price of photomask blanks recovered or shipped by the blankssupplier is changed according to a quality level described in thephotomask blanks.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0107]FIG. 1A is a plan view of a photomask according to an embodimentof the present invention, FIG. 1B is a sectional view along an A-A linein FIG. 1A, FIG. 1C is an enlarged sectional view of a main part of FIG.1B, and FIG. 1D is an enlarged sectional view of a main part of FIG. 1B.

[0108]FIG. 2A is a plan view of a photomask according to an embodimentof the present invention, and FIG. 2B is a sectional view along an A-Aline in FIG. 2A.

[0109]FIG. 3A is a plan view of a photomask according to an embodimentof the present invention, and FIG. 3B is a sectional view along an A-Aline in FIG. 3A.

[0110]FIG. 4 is a flow chart of a technique for manufacturing aphotomask according to an embodiment of the present invention.

[0111]FIG. 5A is a plan view in a step in manufacturing a photomaskaccording to an embodiment of the present invention, and FIG. 5B is asectional view along an A-A line in FIG. 5a.

[0112]FIG. 6A is a plan view in a step in manufacturing a photomasksubsequent to the step in FIG. 5A, and FIG. 6B is a sectional view alongan A-A line in FIG. 6A.

[0113]FIG. 7A is a plan view in a step in manufacturing a photomask inFIGS. 1A to 1C subsequent to the step in FIG. 6A, and FIG. 7B is asectional view along an A-A line in FIG. 7A.

[0114]FIG. 8A is a plan view in a step in manufacturing a photomask inFIGS. 1A to IC subsequent to the step in FIG. 7A, and FIG. 8B is asectional view along an A-A line in FIG. 8A.

[0115]FIG. 9A is a plan view in a step in manufacturing a photomask inFIG. 2A, and FIG. 9B is a sectional view along an A-A line in FIG. 9A.

[0116]FIG. 10A is a plan view in a step in manufacturing a photomask inFIG. 2A, and FIG. 10B is a sectional view along an A-A line in FIG. 10A.

[0117]FIG. 11A is a plan view in a step in manufacturing a photomask inFIG. 1A subsequent to the step in FIG. 8A, and FIG. 11B is a sectionalview along an A-A line in FIG. 11A.

[0118]FIG. 12A is a plan view of a main part of a semiconductor wafer inthe step of forming a pattern, and FIG. 12B is a sectional view along anA-A line in FIG. 12A.

[0119]FIG. 13A is a plan view of a main part of a semiconductor wafer inthe step of forming a pattern subsequent to FIG. 12, and FIG. 13B is asectional view along an A-A line in FIG. 13A.

[0120]FIG. 14A is a plan view of a main part of a semiconductor wafer inthe step of forming a pattern subsequent to the step in FIG. 13A, andFIG. 14B is a sectional view along an A-A line in FIG. 14A.

[0121]FIG. 15A is a plan view in the step of reclaiming a photomask inFIG. 1A according to an embodiment of the present invention, and FIG.15B is a sectional view along an A-A line in FIG. 15A.

[0122]FIG. 16A is a plan view of a photomask in the step of reclaiming aphotomask in FIG. 1A subsequent to FIG. 15A, and FIG. 16B is a sectionalview along an A-A line in FIG. 16A.

[0123]FIG. 17A is a plan view of an example in the step of reclaiming aphotomask in FIG. 1 subsequent to the step in FIG. 16A, and FIG. 17B isa sectional view along an A-A line in FIG. 17A.

[0124]FIG. 18A is a plan view of a photomask according to anotherembodiment of the present invention, FIG. 18B is a sectional view alongan A-A line in FIG. 18A, FIG. 18C is an enlarged sectional view of mainparts and FIG. 18D is an enlarged sectional view of main parts.

[0125]FIG. 19A is a plan view of a photomask according to anotherembodiment of the present invention, and FIG. 19B is a sectional viewalong an A-A line in FIG. 19A.

[0126]FIG. 20A is a plan view of a photomask according to anotherembodiment of the present invention, and FIG. 20B is a sectional viewalong an A-A line in FIG. 20A.

[0127]FIG. 21A is a plan view in a step in manufacturing a photomaskaccording to another embodiment of the present invention, and FIG. 21Bis a sectional view along an A-A line in FIG. 21A.

[0128]FIG. 22A is a plan view in a step in manufacturing a photomaskaccording to another embodiment of the present invention subsequent tothe step in FIG. 21A, and FIG. 22B is an enlarged sectional view of amain part along an A-A line in FIG. 22A.

[0129]FIG. 23A is a plan view in the step of reclaiming a photomaskaccording to another embodiment of the present invention, and FIG. 23Bis an enlarged sectional view of a main part along an A-A line in FIG.23A.

[0130]FIG. 24A is a plan view in the step of reclaiming a photomaskaccording to another embodiment of the present invention, and FIG. 24Bis an enlarged sectional view of a main part along an A-A line in FIG.24A.

[0131]FIG. 25A is a plan view in the step of reclaiming a photomaskaccording to another embodiment of the present invention, and FIG. 25Bis an enlarged sectional view of a main part along an A-A line in FIG.25A.

[0132]FIG. 26A is a plan view of a photomask according to still anotherembodiment of the present invention, and FIG. 26B is a sectional viewalong an A-A line in FIG. 26A.

[0133]FIG. 27A is a plan view of a photomask according to still anotherembodiment of the present invention, and FIG. 27B is a sectional viewalong an A-A line in FIG. 27A.

[0134]FIG. 28A is a plan view of a photomask according to still anotherembodiment of the present invention, and FIG. 28B is a sectional viewalong an A-A line in FIG. 28A.

[0135]FIG. 29 is a flow chart of a technique for manufacturing aphotomask according to still another embodiment of the presentinvention.

[0136]FIG. 30A is a plan view in a step in manufacturing a photomaskaccording to still another embodiment of the present invention in FIG.26, and FIG. 30B is a sectional view along an A-A line in FIG. 30A.

[0137]FIG. 31A is a plan view in a step in manufacturing a photomaskaccording to still another embodiment of the present inventionsubsequent to the step in FIG. 30A, and FIG. 31B is a sectional viewalong an A-A line in FIG. 31A.

[0138]FIG. 32A is a plan view in a step in manufacturing a photomaskaccording to still another embodiment of the present invention in FIGS.27A, and FIG. 32B is a sectional view along an A-A line in FIG. 32A.

[0139]FIG. 33A is a plan view in a step in manufacturing a photomaskaccording to still another embodiment of the present invention in FIGS.28A, and FIG. 33B is a sectional view along an A-A line in FIG. 33A.

[0140]FIG. 34A is a plan view in a step in manufacturing a photomaskaccording to still another embodiment of the present inventionsubsequent to the step in FIG. 31A, and FIG. 34B is a sectional viewalong an A-A line in FIG. 34A.

[0141]FIG. 35A is a plan view in the step of reclaiming a photomaskaccording to still another embodiment of the present inventionsubsequent to the step in FIG. 31A, and FIG. 35B is an enlargedsectional view of a main part along an A-A line in FIG. 35A.

[0142]FIG. 36A is a plan view in the step of reclaiming a photomaskaccording to still another embodiment of the present inventionsubsequent to the step in FIG. 35A, and FIG. 36B is a sectional viewalong an A-A line in FIG. 36A.

[0143]FIG. 37A is a plan view in the step of reclaiming a photomaskaccording to still another embodiment of the present inventionsubsequent to the step in FIG. 35A, and FIG. 37B is a sectional viewalong an A-A line in FIG. 37A.

[0144]FIG. 38A is a plan view of a main part of a photomask according toa different embodiment of the present invention, FIG. 38B is a plan viewof a pattern transferred by the step in FIG. 38A, FIG. 38C is a planview of a main part in the step of performing a reclaiming process ofthe photomask in FIG. 38A, and FIG. 38D is a plan view of a patterntransferred by the photomask in FIG. 38C.

[0145]FIG. 39A is a sectional view of a photomask according to a furtherdifferent embodiment of the present invention, and FIG. 39B is asectional view in the step of performing a reclaiming process of thephotomask in FIG. 39A.

[0146]FIG. 40A is a sectional view of a photomask according to a furtherdifferent embodiment of the present invention, and FIG. 40B is asectional view in the step of performing a reclaiming process of thephotomask in FIG. 40A.

[0147]FIG. 41 is a flow chart for manufacturing a photomask and asemiconductor wafer according to another different embodiment of thepresent invention.

[0148]FIG. 42 is a flow chart for manufacturing a photomask and asemiconductor wafer according to still another different embodiment ofthe present invention.

[0149]FIG. 43A is a plan view of a photomask according to still anotherdifferent embodiment of the present invention, and FIG. 43B is asectional view of the photomask in FIG. 43A.

[0150]FIG. 44A is a plan view of another photomask according to stillanother different embodiment of the present invention, and FIG. 44B is asectional view of the photomask in FIG. 44A.

[0151]FIG. 45 is a sectional view of a main part in a step inmanufacturing a semiconductor integrated circuit device using aphotomask according to an embodiment of the present invention.

[0152]FIG. 46 is a sectional view of a main part in a step inmanufacturing a semiconductor integrated circuit device subsequent tothe step in FIG. 45.

[0153]FIG. 47 is a sectional view of a main part in a step inmanufacturing a semiconductor integrated circuit device subsequent tothe step in FIG. 46.

[0154]FIG. 48 is a sectional view of a main part in a step inmanufacturing a semiconductor integrated circuit device subsequent tothe step in FIG. 47.

[0155]FIG. 49 is a flow chart for explaining manufacturing a photomaskand a reusing route according to another embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0156] Before the present invention is described in detail, the meaningsof terms will be described below.

[0157] 1. A mask (optical mask): is obtained by forming a pattern forshielding light or a pattern for changing a phase of light on maskblanks. The mask also includes a reticle on which a pattern having asize which is several times as large as an actual size is formed. Thefirst major surface of the mask is a pattern surface on which thepattern for shielding light or the pattern for changing the phase oflight is formed, and the second major surface is a surface opposite tothe first major surface.

[0158] 2. Pattern surfaces of a mask are classified into the followingregions. A region “integrated circuit pattern region” in which anintegrated circuit pattern to be transferred is arranged, and a region“peripheral region” around the “integrated circuit pattern region”.

[0159] 3. Although it is not especially limited, in this specification,for the sake of convenience, masks are classified into the followingthree masks from the viewpoint of the manufacturing steps of the masks.That is, the three masks includes mask blanks (to be referred to asblanks hereinafter), a metal mask, and a resist mask. The blanksindicate a mask at the initial stage at which a mask is not completed asa mask on which a desired pattern is to be transferred, and represents amask on which a pattern is not formed in the integrated circuit patternregion and which has a basic configuration required for manufacturing amask and high affinity (compatibility). The metal mask indicates a maskwhich is not completed as a mask and which is at a stage at which apattern made of a metal is formed in the integrated circuit patternregion. The resist mask indicates a mask which is completed as a maskand which is at a stage at which a pattern constituted by a resist filmis formed in the integrated circuit pattern region. On the mask, allpatterns for transferring desired patterns may be constituted by resistfilms, or some patterns may be constituted by metals and resist films.

[0160] 4. A normal mask (binary mask): indicates a general mask obtainedby forming a shade pattern made of a metal, a transparent pattern, and amask pattern on a mask substrate. Unlike the metal mask, the binary maskis completed as a mask on which a desired pattern can be transferredonto a substrate to be processed.

[0161] 5. A wafer indicates a silicon monocrystalline substrate(generally having an almost flat disk-like shape), a sapphire substrate,a glass substrate, an insulation, semi insulation, or semiconductorsubstrate, and a composite substrate thereof. In addition, in asemiconductor integrated circuit device in this application, like asilicon wafer or a sapphire substrate, a wafer is formed on not only asemiconductor or insulating substrate. Unless there is a special noticethat the following is refused, wafers include a wafer formed on anotherinsulating substrate such as glass as in a TFT (Thin-Film-Transistor),an STN (Super-Twisted-Nematic) liquid crystal, and the like.

[0162] 6. A device surface indicates a major surface of a wafer, andindicates a surface on which a device pattern corresponding to aplurality of chip regions is formed by photolithography.

[0163] 7. When a “shade region”, a “shade film”, and a “shade pattern”are mentioned, a shade region, a shade film, and a shade pattern eachhave optical characteristics that not higher then 40% of exposure lightirradiated on the region are transmitted. In general, a region, a film,or a pattern each having optical characteristics that several % to nothigher than 30% is used. On the other hand, when “transparent”, a“transparent film”, a “light-transmitting region”, and a“light-transmitting pattern” are mentioned, transparent, a transparentfilm, a light-transmitting region, and a light-transmitting pattern eachhave optical characteristics that 60% or more of exposure lightirradiated on the region are transmitted. In general, a film, a region,or a pattern each having optical characteristics that 90% or more ofexposure light irradiated on the region is transmitted is used.

[0164] 8. A hole pattern: indicates a micropattern such as a contacthole or a through hole having a two-dimensional size which is almostequal to or larger than an exposure wavelength on a wafer. In general,on a mask, a hole pattern has a square shape, a rectangular shape whichis similar to a square shape, or an octagonal shape. However, on awafer, a circular hole pattern is often used.

[0165] 9. A line pattern: indicates a belt-like pattern which formswires or the like on a wafer.

[0166] If necessary for the sake of convenience, the followingembodiments will be described such that the embodiments are divided intoa plurality of sections or embodiments. Unless there is a specialnotice, these sections and embodiments are not unrelated to each otherand have the following relationship. That is, one embodiment constitutesa modification, details, supplement, or the like of a part or whole ofthe other embodiment.

[0167] In the following embodiments, when the number of elements and thelike (including the number of elements, numeral values, quantities,ranges, and the like) are mentioned, unless there is a special notice,or unless the numbers are apparently limited to specific numbers, thenumbers are not limited to specific numbers, and the numbers may beequal to or larger than the specific numbers.

[0168] In addition, in the following embodiments, the constituentelements (including element steps and the like) are not necessary as amatter of course unless there is a special notice and unless it isconsidered that constituent elements are apparently necessary.

[0169] Similarly, in the following embodiments, when the shapes,positional relationship, and the like of constituent elements and thelike are mentioned, unless there is a special notice and unless it isconsidered that the following description is apparently wrong inprinciple, the shapes of the constituent elements substantially includeshapes which are approximate to or similar to the shapes of theconstituent elements. This condition is also satisfied with respect tothe numeral values and ranges.

[0170] In all the drawings for explaining the embodiments, the samereference numerals denote parts having the same functions, andrepetitive descriptions will be omitted.

[0171] In the drawings used in the embodiments, in order to make it easyto see the drawings, although the drawings are plan views, a shadeportion (a shade film, a shade pattern, a shade region, or the like) anda resist film are hatched.

[0172] In the embodiments, a MIS.FET (Metal Insulator SemiconductorField Effect Transistor) representing a field effect transistor isabbreviated as a MIS, a p-channel type MIS.FET is abbreviated as a pMIS,and an n-channel type MIS.FET is abbreviated as an nMIS.

[0173] Embodiments of the present invention will be described below withreference to the accompanying drawings.

[0174] (First Embodiment)

[0175] In this embodiment, a mask having a metal frame formed on theperiphery of an integrated circuit pattern region of the mask will bedescribed below. An example, a mask according to this embodiment isshown in FIGS. 1A to 1D to FIGS. 3A and 3B. FIGS. 1A, 2A, and 3A areplan views of the masks, FIGS. 1B, 2B, and 3B are sectional views alongA-A lines in FIGS. 1A, 2A, and 3A, respectively. FIGS. 1C and 1D areenlarged sectional views of main parts of the masks.

[0176] These masks M1 a, M1 b, and M1 c indicate reticles fortransferring original images of integrated circuit patterns having sizeswhich are about 1 to 10 times actual sizes onto wafers through reductionprojection optics or the like. In this case, although a mask used totransfer a line pattern onto a wafer is illustrated, the spirit andscope of the present invention can be applied to not only the mask, butalso a case in which, for example, a hole pattern or the like istransferred. When the masks M1 a and M1 b are used, a positive typeresist film is used on the wafer. When the mask M1 c is used, a negativetype resist film is used on the wafer. Mask blanks 1 for the masks M1 a,M1 b, and M1 c are constituted by transparent synthetic quartz glasssubstrates or the like each having a square shape and a thickness ofabout 6 mm. Although is not specified, the thickness of the mask blanks1 are preferably, e.g., about 4 mm or more from a viewpoint ofprocessability and assuring mechanical strength. However, inconsideration of an influence of a mask weight on scanning accuracy, athickness of, e.g., about 20 mm or less is preferably used.

[0177] The mask M1 a in FIG. 1 illustrates a mask in which the peripheryof a semiconductor chip serves as a shade region. In the integratedcircuit pattern region at the center on a major surface of the maskblanks 1 on the mask M1 a, a light-transmitting region 2 a having a flatrectangular shape is formed, and the major surface of the mask blanks 1is partially exposed. On the first major surface of the mask blanks 1 inthe integrated circuit pattern region, a shade pattern 3 a fortransferring an integrated circuit pattern onto the wafer is arranged.In this case, it is illustrated that only the shade pattern 3 aconstituted by a resist film is arranged in the integrated circuitpattern region, and the shade pattern 3 a is transferred as a linepattern (integrated circuit pattern) on the wafer.

[0178] In this embodiment, the shade pattern 3 a is formed by a resistfilm. For this reason, as will be described later, the shade pattern 3 acan be relatively easily removed. A new shade pattern 3 a can easilyformed within short time. The resist film forming the shade pattern 3 aabsorbs exposure light such as a KrF excimer laser beam (wavelength of248 nm), an ArF excimer laser beam (wavelength of 193 nm), or an F²laser beam (wavelength of 157 nm). The resist pattern has a shadefunction which is almost the same as that of a shade pattern made of ametal.

[0179] The shade pattern 3 a may be constituted by a single resist filmas shown in FIG. 1C, or may be constituted such that a photosensitiveorganic film 3 a 2 is stacked on a photoabsorptive organic film 3 a 1.When a laminate structure constituted by the photoabsorptive organicfilm 3 a 1 and the photosensitive organic film 3 a 2 is employed,sufficient attenuation can be obtained with respect to exposure lightsuch as an i-line (wavelength of 365 nm) or a KrF excimer laser having awavelength of 200 nm or more.

[0180] The materials or the like of the resist film will be describedlater. A technique for forming a shade pattern by a resist film isdescribed in Japanese Patent Application No. 11-185221 (filed on Jun.30, 1999) filed by the present inventors.

[0181] The periphery (the peripheral region) of an integrated circuitpattern region on the first major surface of the mask blanks 1 in FIG. 1is covered with a shade pattern 4 a (frame: a second shield portion madeof a metal) from the periphery of the integrated circuit pattern regionto the periphery of the mask blanks 1. The shade pattern 4 a is formedby depositing, e.g., chromium (Cr) or chromium oxide on chromium.However, the material of the shade pattern 4 a is not limited tochromium or chromium oxide, and can be variously changed.

[0182] For example, a refractory metal such as tungsten (W), molybdenum(Mo), tantalum (Ta), or titanium (Ti), a refractory metal nitride suchas tungsten nitride (WN), a refractory metal silicide (compound) such astungsten silicide (Wsix) or molybdenum silicide (MoSix), or a laminatefilm made of these materials may be used. When the mask according tothis embodiment is used, after the shade pattern 3 a constituted by aresist film is removed, and the mask is cleansed and used again. Forthis reason, as the material of the shade pattern 4 a, a material havinggood resistance to stripping and good resistance to abrasion ispreferably used. A refractory metal such as tungsten has good resistanceto oxidation, good resistance to abrasion, and good resistance ofstripping. Therefore, the refractory metal is preferably used as thematerial of the shade pattern 4 a. This shade pattern 4 a portion servesas a region with which a setting portion of an exposure device isbrought into contact when the mask M1 a is set on the mask M1 a. Whenthe shade pattern 4 a is arranged, the mask M1 a is set on the exposuredevice without generating particles.

[0183] In the peripheral region of the mask blanks 1 in FIG. 1, alight-transmitting pattern 2 b for forming a mark for detectinginformation of the mask M1 a is formed. This light-transmitting pattern2 b is a pattern for directly detecting positional information of themask M1 a from the mask M1 a itself when a predetermined pattern isdelineated on the mask M1 a by using, e.g., an electronic delineationdevice or the like. In the peripheral region of the mask M1 a, alight-transmitting pattern 2 c for forming a mark for detectinginformation of the mask M1 a is also formed on the further outside ofthe light-transmitting pattern 2 b. The light-transmitting pattern 2 cis used as, e.g., an alignment mark or a correction mark or the likeused to manufacture a mask. When the mask M1 a is set on a predetermineddevice such as a detection device or an exposure device, the alignmentmark is used to align the mask M1 a, the detection device, the exposuredevice, and the like by detecting the position of the mask M1 a. Thecorrection mark is used when pattern offset, the state of the shape of apattern, or pattern transfer accuracy is measured and when focus driftof the exposure device is automatically corrected. Thelight-transmitting patterns 2 b and 2 c are not transferred onto awafer.

[0184] The mask M1 b in FIG. 2 illustrates a mask which is designed suchthat the peripheral contour of a semiconductor chip serves as a shaderegion. Since the integrated circuit pattern region of the mask M1 b isthe same as that of the mask M1 a, a description thereof will beomitted. On the first major surface of the mask blanks 1, the peripheryof the integrated circuit pattern region is surrounded by a belt-likeshade pattern (shade portion made of a metal) 4 b. Most of the outsideof the peripheral region of the mask M1 b serves as a light-transmittingregion 2 d by removing a shade from. In the light-transmitting region 2d, a shade pattern 4 c for forming a mark for detecting information ofthe mask M1 b is formed. This shade pattern 4 c is a mark having thesame function as that of the light-transmitting pattern 2 b of the maskM1 a. In the peripheral region of the mask M1 b, a shade pattern 4 dhaving the same function as that of the light-transmitting pattern 2 cof the mask M1 a is formed on a further outside of the shade pattern 4c. The shade patterns 4 c and 4 d are not transferred onto the wafer.The belt-like shade patterns 4 b to 4 d are formed by the same materialis processed in the same pattern processing. The structures (thematerials, the laminate structures, and the like) of the belt-like shadepatterns 4 b to 4 d are formed of the same metal of the shade pattern 4a. The shade patterns 4 c and 4 d for marks may be constituted by resistfilms. Detection of a mark may use a normal halogen lamp or the like. Inthis case, a shade pattern for a mark constituted by the resist film mayhave the laminate structure comprising the photoabsorptive organicmaterials and photosensitive organic materials described above.

[0185] The mask M1 c in FIG. 3 illustrates an inverted pattern of eachof the masks M1 a and M1 b. The basic structure (structure of theblanks) of the mask M1 c is the same as that of the mask M1 a. Anintegrated circuit pattern region (i.e., the light-transmitting region 2a) on the first major surface of the mask blanks 1 is covered with ashade film 3 b. The structures (the material, the laminate structure,and the like) of the shade film 3 b are the same as those of the shadepattern 3 a. The peripheral portion of the shade film 3 b is stacked ona part of the shade pattern 4 a. The shade film 3 b in the integratedcircuit pattern region is partially removed to form a light-transmittingpattern 2 e. By the light-transmitting pattern 2 e, a line pattern orthe like is transferred onto the wafer. The structure of the maskpattern constituted by the shade film 3 b and the light-transmittingpattern 2 e can also be applied to the mask M1 b in FIG. 2.

[0186] A method of manufacturing the masks M1 a, M1 b, and M1 c, amethod of using the masks, and a method of reclaiming (reusing) themasks will be described below with reference to FIGS. 5A and 5B to FIGS.17A and 17B along the flow chart in FIG. 4. FIGS. 5B to 17B aresectional views along A-A lines in FIGS. 5A to 17A, respectively.

[0187] As shown in FIGS. 5A and 5B, blanks obtained by adhering a shadefilm 4 made of a metal to the entire surface of the first major surfaceof the mask blanks 1 were prepared (step 101). The structures (thematerial, the laminate structure, and the like) of the shade film 4 arethe same as those of the shade pattern 4 a. When oxygen plasma ashing isused to strip the shade pattern 3 a and the shade film 3 b constitutedby the resist films, it is preferable to select a metal such as tungstenhaving resistance to oxidation because good resistance to stripping andgood resistance to abrasion are obtained. When the masks M1 a and M1 care used, since the shade films 4 are removed from the integratedcircuit pattern regions at the centers of the major surfaces, the shadefilms 4 corresponding to the portions may have defects such as pin holeswithout any trouble. In addition, when the mask M1 b is used, since theshade film 4 at the center of the major surface and on the periphery isremoved, the shade film 4 corresponding to both the portions may havethe defects without any trouble.

[0188] Subsequently, as shown in FIGS. 6A and 6B, after a resist film 5is coated on the shade film 4 made of a metal (step 102), patterndelineation and development are performed to form a resist pattern 5 aas shown in FIGS. 7A and 7B (steps 103 and 104). After the shade film 4made of a metal is etched by using the resist pattern 5 a as a mask(step 105), the resist pattern 5 a is stripped (step 106) to form ametal shade pattern 4 a (frame) as shown in FIGS. 8A and 8B. The formedmetal shade pattern 4 a is a pattern which covers the periphery of theintegrated circuit pattern region, and light-transmitting patterns 2 band 2 c for forming a reticle alignment mark, a base line adjustmentmark, a wafer alignment mark of the exposure device, and the like areformed in the region of the shade pattern 4 a. The masks shown in FIGS.5A and 5B, FIGS. 6A and 6B, and FIGS. 8A and 8B correspond to the blanksdescribed above.

[0189] The blanks shown in FIG. 8 can be used to manufacture both themasks M1 a and M1 c. FIGS. 9A and 9B and FIGS. 10A and 10B illustrateblanks obtained through the step 101 to the step 106 when the mask M1 bis used. On the first major surface of the mask blanks 1 in FIGS. 9A and9B, the shade pattern 4 b which comprises of a metal (shade film 4) andthe shade patterns 4 c and 4 d for marks are formed. On the first majorsurface of the mask blanks 1 in FIGS. 10A and 10B, only the shadepattern 4 b is formed. The blanks in FIGS. 10A and 10B illustrate blanksobtained when the shade pattern for a mark is formed by the shadepattern constituted by the resist film.

[0190] Thereafter, defect inspection is performed (step 107). If adefect is detected, defect correction is performed (step 108). If nodefect is detected, the cleaning process is performed (step 109).

[0191] As shown in FIGS. 11A and 11B, a resist film (photosensitiveorganic film) 3 having a thickness of about 150 nm is coated on thefirst major surface of the mask blanks 1 (blanks) shown in FIGS. 8A and8B and the like (step 110), and mask pattern delineation and developmentare performed to form the shade pattern 3a or the shade film 3 bconstituted by the resist films shown in FIGS. 1A to 1D to FIGS. 3A and3B, thereby manufacturing the masks M1 a, M1 b, and M1 c (steps 111 and112).

[0192] As this resist film 3, for example, a material containing, as amain component, e.g., poly(-methylstyrene-co-chloroacrylic acid), anovolac resin and quinone diazide, a novolac resin andpoly(2-methylpentene-co-sulfone), chloromethylated polystyrene, or thelike was used. A so-called chemical amplification resist or the likeobtained by mixing an acid generator with a phenol resin or a novolacresin such as a polyvinyl phenol resin can be used. As the material ofthe resist film 3 used in this case, a material having shadecharacteristics for the light source of the projection aligner andcharacteristics that sensitivity to a light source of a patterndelineation device, e.g., an electron beam or light having a wavelengthof 230 nm or more must be used. The material of the resist film 3 is notlimited to the materials described above, can be variably changed. Thethickness is not limited to 150 nm, and the thickness which satisfiesthe conditions may be used.

[0193] When a polyphenol-based or novolac-based resin is formed as afilm having a thickness of about 100 nm, a transmittance is almost 0 ata wavelength of, e.g., about 150 nm to 230 nm, and the film has asufficient mask effect with respect to, e.g., an ArF excimer laser beamhaving a wavelength of 193 nm, an F² laser beam having a wavelength of157 nm, or the like. In this case, although vacuum ultraviolet lighthaving a wavelength of 200 nm or less is used, light to be used is notlimited to the ultraviolet light. As a mask material for a krF excimerlaser beam having a wavelength of 248 nm, another material must be used,a photoabsorptive material or a shade material must be added to theresist film, or a laminate film constituted by a photoabsorptive organicfilm and a photosensitive organic film is used as the resist film asdescribed above. After the shade pattern 3 a and the shade film 3 bconstituted by the resist film are formed, addition of a heat treatmentstep to improve resistance to exposure light irradiation or execution ofa so-called hardening process of the resist film for stronglyirradiating ultraviolet light in advance is effective.

[0194] The masks M1 a, M1 b, and M1 c were set in an exposure device,and test exposure is performed on the wafers (step 113). The wafers aresubjected to a development process to perform defect inspection oftransfer patterns formed on the wafers (step 114). A defect occurrencemode between a plurality of shots was examined to extract a mask defect,and the presence/absence of fatal defect is decided. More specifically,defects detected at the same position in one shot of a plurality ofshots was regarded as a mask defect. The case in which test exposure isperformed on a wafer to perform defect inspection has been described.However, the present invention is not limited to this case. A method ofinspecting defects of the masks M1 a, M1 b, and M1 c without performingexposure may be employed (the method is similarly employed in defectinspection of a resist mask).

[0195] On the masks M1 a, M1 b, and M1 c which does not pass the defectinspection, the shade pattern 3 a or the shade film 3 b constituted bythe resist film were stripped (step 115), cleansing was performed (step116), and particle check for checking the presence/absence or the likeof particles or scratches was performed (step 117). When the number ofchecked particles is a predetermined number or small, the masks werereclaimed as reclamation blanks (states of the blanks shown in FIGS. 8Aand 8B to FIGS. 10A and 10B or the like). More specifically, coating ofthe resist film for forming a shade portion was started again to producethe masks M1 a, M1 b, and M1 c (reclamation process). An integratedcircuit pattern (the shade pattern 3 a, the light-transmitting pattern 2e, or the like) formed on the mask after the mask is reclaimed may bethe same as the pattern before the reclamation or may be different fromthe pattern before the reclamation.

[0196] The masks M1 a, M1 b, and M1 c which pass the wafer defectinspection are used in exposure of wafers (step 118). An example of theexposure process will be described below. FIG. 12A is a plan view of amain part of a wafer 6 obtained before the exposure process isperformed, and FIG. 12B is a sectional view along an A-A line in FIG.12A. The wafer 6 serving as a substrate to be projected comprises, e.g.,silicon monocrystal. An insulating film 7 is deposited on a majorsurface of the wafer 6. A conductive film 8 is deposited on the entiresurface of the insulating film 7. A normal resist film 9 is deposited tohave a thickness of, e.g., about 300 nm. When the masks M1 a and M1 bare used, for example, a positive type resist film is used as the resistfilm 9. When the mask M1 c is used, a negative type resist film is usedas the resist film 9.

[0197] As projection light of a reduction projection exposure device,e.g., an ArF excimer laser having a wavelength of 193 nm was used. As anumeral aperture NA of a projection lens, e.g., 0.68 was used. As thecoherency of the light source, e.g., 0.7 was used. Alignment between theused masks M1 a, M1 b, and M1 c and the reduction projection exposuredevice was performed by detecting the light-transmitting patterns 2 c orthe shade patterns 4 d of the masks M1 a, M1 b, and M1 c.

[0198] Thereafter, the integrated circuit patterns on the masks M1 a, M1b, and M1 c were projected on the major surface of the wafer 6. Theresultant structure was subjected to normal heat treatment and a normaldevelopment step to form a resist pattern 9 a shown in FIGS. 8A and 8B.Thereafter, an etching process was performed to the conductive film 8 byusing the resist pattern 9 a as an etching mask to form a conductivefilm pattern 8 a as shown in FIGS. 14A and 14B. As a result, patterntransfer characteristics which were the same as those in the exposureusing the normal mask could be obtained. For example, a line-and-spaceof 0.19 μm could be formed at a focal depth of 0.4 μm.

[0199] After the exposure process described above was performed, theresist films (the shade pattern 3 a and the shade film 3 b) on the masksM1 a, M1 b, and M1 c were stripped after the masks were wasted. Themasks M1 a, M1 b, and M1 c were cleaned, and particle check wasperformed (steps 115, 116, and 117). A mask which did not pass theparticle check was cleaned again and subjected to particle check (steps116 and 117). A mask which passed the particle check was reclaimed asreclamation blanks (blanks shown in FIGS. 8 to 10 or the like). Asdescribed above, in this embodiment, the masks can be reclaimed. Forthis reason, the cost of materials, the cost of steps, and the cost offuel in manufacturing masks can be reduced. Therefore, the cost of themask can be considerably reduced. A period of time required formanufacturing a mask can be considerably shortened. In addition, theinvention is also effective to saving of resources or a countermeasureagainst destruction of the environment.

[0200] The steps in reclaiming a mask according to this procedure willbe described below with reference to FIGS. 15A and 15B to FIGS. 17A and17B. Although the mask M1 a will be mainly illustrated, the sameprocesses as those performed to the mask M1 a are performed to the othermasks M1 b and M1 c.

[0201] The shade pattern 3 a (the shade film 3 b in the mask M1 c )constituted by a resist film was stripped from the exposed mask M1 a by,as shown in FIGS. 15A and 15B, for example, n-methyl-2-pyrolidoneorganic solvent. The shade pattern 3 a or the shade film 3 b may also bestripped by a heated amine-based organic solvent or acetone. The shadepattern 3 a or the shade film 3 b may also be removed by a tetra methylammonium hydroxide (TMAH) aqueous solution, ozone sulfuric acid, or amixture of a hydrogen peroxide solution and concentrated sulfuric acid.When the TMAH aqueous solution was used, if the concentration of theTMAH aqueous solution was set to be about 5%, the resist film (the shadepattern 3 a or the shade film 3 b) could be preferably stripped withoutcorroding the metal (the shade patterns 4 a and 4B or the like).

[0202] As another method of removing a resist film (the shade pattern 3a, the shade film 3 b, or the like), an oxygen plasma ashing method canalso be used. The oxygen plasma ashing has the maximum capability ofstripping. This method is especially effective when a hardening processof the resist film is performed to the shade pattern 3 a (the shade film3 b of the mask M1 c ) constituted by the resist film on the mask M1 c.Since the resist film (the shade pattern 3 a, the shade film 3 b, or thelike) subjected to the hardening process is hardened, the resist filmmay be completely removed by the above chemical removing method.

[0203] The resist film (the shade pattern 3 a, the shade film 3 b, orthe like) may be mechanically stripped by peeling. More specifically, anadhesive tape is adhered to a surface on which the shade pattern 3 a(the shade film 3 b of the mask M1 c) constituted by the resist film ofthe mask M1 a is formed, and the adhesive tape is stripped to strop theresist film (the shade pattern 3 a or the shade film 3 b). In this case,since a vacuum state is not necessarily made, the resist film (the shadepattern 3 a or the shade film 3 b) can be relatively easily strippedwithin a short period of time.

[0204] After the step of removing a resist film (the shade pattern 3 aor the shade film 3 b), the mask M1 a is subjected to a cleaning processto remove particles 50 on the surface of the mask M1 a. In this manner,the mask is reclaimed to have the state of the mask blanks shown inFIGS. 8A and 8B to FIGS. 10A and 10B. In cleaning performed in thiscase, for example, a combination of cleaning using an ozone sulfuricacid and brush scrubber is used. However, this method can be variablychanged into any method which has high capability of removing particlesand which does not corrode the metal (the shade patterns 4 a to 4 d).

[0205] As shown in FIGS. 16A and 16B, like the above description, theresist film 3 is coated on the mask blanks 1 (blanks) shown in FIGS. 8Aand 8B to FIGS. 10A and 10B, and mask pattern delineation anddevelopment are performed to form the shade pattern 3 a (the shade film3 b in the mask M1 c) constituted by the resist film as shown in FIGS.17A and 17B, so that the mask M1 a is manufactured. A case in which ashade pattern 3 a which is different from the shade pattern 3 a shown inFIGS. 1A to 1D in shape and arrangement is formed is illustrated. As amatter of course, the same pattern which is the same as the shadepattern 3 a in FIG. 1 may be formed. In a description of methods ofmanufacturing and reclaiming a mask, a case in which a shade pattern ora shade film is formed on a single resist film is explained. However,this method can also be similarly applied to a case in which the shadeportion is constituted by a laminate layer constituted by aphotosensitive organic film and a photoabsorptive organic film.

[0206] According to this embodiment, the following merits can beobtained. (1) The number of steps is small because removal and polishingof a metal are not required. (2) The mask blanks 1 are not thinned everyreclamation because polishing is not required, and the mask can berepeatedly reclaimed. (3) The mask can be reused in a state in which ametal frame (shade pattern 4 a) on which a pattern required not toreclaim the mask into the mask blanks 1 but to set the mask on anexposure device is formed, and the steps in manufacturing a mask can beconsiderably reduced. (4) Since the inspection step for the mask blanks1 (blanks) can be eliminated, or since inspection accuracy can beconsiderably moderated in comparison with a case in which conventionalreuse of a mask is supposed, the number of steps in manufacturing a maskcan be reduced. (5) Since particles having fine particles as cores aregenerated because a metal layer is formed by sputtering when metal suchas chromium is used as the material of a shade portion, a yield ofreclamation of masks is small, in this embodiment, since a shade portion(attenuation film) used in reusing is a resist film formed by coating, asmall number of particles of the shade portion are generated, i.e., alarge yield can be achieved.

[0207] (Second Embodiment)

[0208] In this embodiment, a mask in which only a shade patternconstituted by a resist film is formed in an integrated circuit patternof the mask will be described below. An example of the mask according tothis embodiment is shown in FIGS. 18A and 18D to 20A and 20B. FIGS. 18A,19A, and 20A are plan views of masks, and FIGS. 18B, 19B, and 20B aresectional views along A-A lines in FIGS. 18A, 19A, and 20A,respectively. FIGS. 1C and 1D are enlarged sectional views of main partsof a mask.

[0209] In a mask M2 a in FIGS. 18A to 18D, the shade pattern 4 a (metalframe) of the mask M1 a is formed by a shade pattern 3 c constituted bya resist film. The shade pattern 3 c is formed such that a resistmaterial which is the same as that of the shade pattern 3 a is processedin pattern processing of the shade pattern 3 a of the resist film. Theother configuration of the mask M2 a is the same as that of the mask M1a according to the first embodiment. However, in the shade pattern 3 c,a portion with which the stage of an exposure device or the like isbrought into mechanical contact is removed to expose the mask blanks 1.In this manner, generation of particles in setting a mask can besuppressed or prevented.

[0210] In a mask M2 b shown in FIGS. 19A and 19B, the shade patterns 4 bto 4 d of the mask M1 b in FIGS. 2A and 2B are formed by shade patterns3 d to 3 f constituted by resist films, respectively. The shade patterns3 d to 3 f are formed by processing the same resist material as that ofthe shade pattern 3 a in pattern processing of the shade pattern 3 a ofthe resist film. The other configuration of the mask M2 b is the same asthat of the mask M1 b according to the first embodiment.

[0211] In a mask M2 c in FIGS. 20A and 20B, the shade pattern 4 a of themask M1 c in FIG. 3A and 3B is also formed by a shade film 3 bconstituted by a resist film. More specifically, the shade film 3 bconstituted by the resist film is deposited on the entire surface of thefirst major surface of mask blanks 1, and the shade film 3 b ispartially removed to form a light-transmitting pattern 2 e fortransferring an integrated circuit pattern and light-transmittingpatterns 2 b and 2 c for a mark. The resist film on a portion with whichthe stage of an exposure device is brought into mechanical contact isalso removed. The other configuration of the mask M2 c is the same asthat of the mask M1 c according to the first embodiment.

[0212] When the masks M2 a, M2 b, and M2 c are used, the shade patterns3 a and 3 c to 3 f and the shade film 3 b may be constituted by singlefilms constituted by resist films as shown in FIG. 18C. As shown in FIG.18D, a configuration in which a photosensitive organic film 3 a 2 isstacked on a photoabsorptive organic film 3 a 1 may be employed.

[0213] Methods of manufacturing, using, and reclaiming (reusing) themasks M2 a, M2 b, and M2 c will be described below with reference toFIGS. 21A and 21B to FIGS. 25A and 25B. FIGS. 21B, 22B, 23B, 24B, and25B are sectional views along A-A lines in FIGS. 21A, 22A 23A, 24A, and25A, respectively.

[0214] As shown in FIG. 21A and 21B, blanks formed by the mask blanks 1are prepared, and a resist film (photosensitive organic film) 3 iscoated on the first major surface of the mask blanks 1 to have athickness of about 150 nm as shown in FIGS. 22A and 22B. Subsequently,mask pattern delineation and development are performed to the resistfilm 3 to form the shade patterns 3 a and 3 c to 3 f or the pattern ofthe shade film 3 b constituted by the resist films shown in FIGS. 18A to18D to FIGS. 20A and 20B, so that the masks M2 a, M2 b, and M2 c (resistmasks) are manufactured. Thereafter, the masks M2 a, M2 b, and M2 c wereset on an exposure device to perform test exposure on the wafers, anddefect inspection for the transfer patterns was performed by the samemanner as that in the first embodiment. Not only the method ofperforming detect inspection by test exposure, but also a method ofinspecting defects of the masks M2 a, M2 b, and M2 c without exposuremay be employed.

[0215] On the masks M2 a, M2 b, and M2 c which did not pass the defectinspection, the shade patterns 3 a and 3 c to 3 f or the shade film 3 bconstituted by the resist films were stripped. After the masks M2 a, M2b, and M2 c were cleaned, particle check was performed. When the numberof checked particles each having a predetermined size or larger wassmaller than a predetermined number, the blanks are reused asreclamation blanks (blanks in FIGS. 21A and 21B. An integrated circuitpattern (the shade pattern 3 a, the light-transmitting pattern 2 e, orthe like) formed on the reclaimed mask may have a pattern which is thesame as the pattern obtained before the reclamation or a pattern whichis different from the pattern obtained before the reclamation. The masksM2 a, M2 b, and M2 c which pass the wafer defect inspection are used inexposure for the wafers as in the first embodiment.

[0216] The resist films (the shade patterns 3 a and 3 c to 3 f or theshade film 3 b) of the exposed masks M2 a, M2 b, and M2 c were strippedby the same manner as that of the first embodiment as shown in FIG. 23Aand 23B, particles 50 were removed by cleaning, and as shown in FIGS.24A and 24B, blanks constituted by the mask blanks 1 were reclaimed. Inthis cleaning process, cleaning using a 1-wt % hydrofluoric acid aqueoussolution, cleaning using an ozone sulfuric acid, and brush scrubber wereused. The concentration of 1 wt % of the hydrofluoric acid aqueoussolution is only an example, and the concentration is not limited to 1wt %. The concentration is set in consideration of the following case.That is, the concentration is so low that cleaning effect isdeteriorated, and the concentration is so high that a glass surface(surface of the mask blanks 1) is coarsened to deteriorate thetransmittance. When an amount of etching of the mask blanks 1 obtainedby hydrofluoric acid cleaning is not specified, any problem is notposed. It is important that the mask blanks 1 obtained after thehydrofluoric acid cleaning process are baked at a temperature of, e.g.,200° C. or higher to evaporate fluorine adhered to the surface for thefollowing reason. That is, when hydrofluoric acid remains on the surfaceof the mask blanks 1, the hydrofluoric acid reacts with achemical-amplification-type photosensitive composition (resist film)when the mask is reused to deteriorate the resist shape, and delineationsensitivity is changed. This baking may be performed after the finalcleaning is performed. When ozone sulfuric acid cleaning is performed,the substrate is advantageously cleaned with a mixture of ammonia and ahydrogen peroxide solution in advance because the substrate is notcloudy when the substrate is left.

[0217] As in the above description, the resist film 3 is coated on themask blanks 1 shown in FIGS. 24A and 24B, and, as shown in FIG. 25A and25B, the shade patterns 3 a and 3 c (or the shade patterns 3 d to 3 f orthe shade film 3 b) constituted by the resist films are formed byperforming mask pattern delineation and development to manufacture themask M2 a. In this case, such a case is illustrated that a shade pattern3 a having a shape or an arrangement which is different from that of theshade pattern 3 a shown in FIGS. 18A to 18D is formed. As a matter ofcourse, the same pattern as the shade pattern 3 a shown in FIGS. 18A to18D may be formed. In the description of the method of manufacturing andreclaiming (reusing) a mask, a case in which a shade pattern or a shadefilm is formed by a single resist film is explained. The methods canalso be applied to a case in which the shade portion is constituted by alaminate film constituted by a photosensitive organic film and aphotoabsorptive organic film.

[0218] According to this embodiment, the same effects as the effects(for example, the effects (1), (2), (4), and (5)) of the firstembodiment can be obtained.

[0219] (Third Embodiment)

[0220] In this embodiment, a mask in which a shade pattern constitutedby a resist film and a shade pattern made of a metal are formed in anintegrated circuit pattern region of the mask will be described below.An example of the mask according to this embodiment will be describedbelow with reference to FIGS. 26A and 26B to 28A to 28B. FIGS. 26A, 27A,and 28A are plan views of masks, and FIGS. 26B, 27B, and 28B showsectional views along A-A lines in FIGS. 26A, 27A, and 28A,respectively.

[0221] On a mask M3 a shown in FIGS. 26A and 26B, both a shade pattern(first shade portion made of a metal) 4 e made of a metal and a shadepattern 3 a constituted by a resist film are formed in an integratedcircuit pattern region of the first major surface of the mask blanks 1.In this case, the shade pattern 3 a constituted by the resist film ispartially (in only a region RE). The shade pattern 4 e is formed suchthat a metal material is processed in pattern processing of the shadepattern 4 a. In this case, a line pattern or the like is transferred ona wafer by the shade patterns 4 e and 3 a. In particular, the shadepattern 4 e made of the metal is made into an IP in a pattern which isslightly corrected in design or process, a system LSL (Large ScaleIntegrated circuit), or the like, and is used as a pattern fortransferring a generally used circuit portion. The shade pattern 3 aconstituted by the resist film is a pattern for transferring a circuitportion which can be easily changed and corrected. The otherconfiguration of the mask M3 a is the same as that of the mask M1 aaccording to the first embodiment.

[0222] Also in a mask M3 b shown in FIGS. 27A and 27B, both a shadepattern 4 e made of a metal and a shade pattern 3 a constituted by aresist film are formed in an integrated circuit pattern region of thefirst major surface of the mask blanks 1. The shade pattern 4 e isformed such that a metal material is processed in pattern processing ofthe shade patterns 4 b to 4 d. The other configuration of the mask M3 bis the same as that of the mask M1 b according to the first embodiment.

[0223] In addition, almost entire area of the first major surface,including the integrated circuit pattern region, of the mask blanks 1 ona mask M3 c shown in FIGS. 28A and 28 is coated with a shade film 4 fmade of a metal. The shade film 4 f comprises the same material as thatof the shade pattern 4 a. A part of the shade film 4 f in the integratedcircuit pattern region is removed to form a light-transmitting pattern 2e for transferring an integrated circuit pattern and a squarelight-transmitting region. The square light-transmitting region iscoated with a shade film 3 b. The shade film 3 b is partially removed toform the light-transmitting pattern 2 e onto which the integratedcircuit pattern is transferred. The other configuration of the mask M3 cis the same as that of the mask M1 c of the first embodiment.

[0224] On these masks M3 a, M3 b, and M3 c, the shade pattern 3 a andthe shade film 3 b may be constituted by a single resist film as shownin FIG. 18C, and the shade pattern 3 a and the shade film 3 b may beconstituted by a film obtained by stacking a photosensitive organic film3 a 2 on a photoabsorptive organic film 3 a 1.

[0225] A method of manufacturing the masks M3 a, M3 b, and M3 c, amethod of using the masks, and a method of reclaiming (reusing) themasks will be described below along the flow chart in FIG. 29. FIGS. 30Bto 37B are sectional views along A-A lines in FIGS. 30A to 37A,respectively.

[0226] As in the first embodiment described above, as shown in FIGS. 5Aand 5B, blanks obtained by adhering a shade film 4 made of a metal tothe entire surface of the first major surface of the mask blanks 1 areprepared (step 301). As shown in FIGS. 6A and 6B, after a resist film 5is coated on the shade film 4 (step 302), pattern delineation anddevelopment are performed to form resist patterns 5 a and 5 b as shownin FIGS. 30A and 30B (steps 303 and 304). The resist pattern 5 a is amask pattern for forming the shade pattern 4 a, and the resist pattern 5b is a mask pattern for forming the shade pattern 4 e. Subsequently,after the shade film 4 made of a metal is etched by using the resistpatterns 5 a and 5 b as masks (step 305), the resist patterns 5 a and 5b are stripped (step 306) to form metal shade patterns 4 a and 4 e asshown in FIGS. 31A and 31B. This stage is the stage of a metal mask. Themetal shade pattern 4 a formed at this time is a pattern which coversthe periphery of the integrated circuit pattern region, andlight-transmitting patterns 2 b and 2 c for forming a reticle alignmentmark, a base line adjustment mark, a wafer alignment mark, and the likeare formed in the region of the shade pattern 4 a. The metal shadepattern 4 e formed in the integrated circuit pattern region is a patternfor transferring the integrated circuit pattern onto the wafer.

[0227]FIGS. 32A and 32B and FIGS. 33A and 33B illustrate metal masksobtained through steps 301 to 306 by using the masks M3 b and M3 c,respectively. On the first major surface of the mask blanks 1 shown inFIGS. 32A and 32B, the shade pattern 4 b made of a metal (shade film 4)and the shade patterns 4 b to 4 d for mask are formed in a peripheralregion, and the shade pattern 4 e made of a metal (shade film 4) isformed in the integrated circuit pattern region. The first major surfaceof the mask blanks 1 shown in FIGS. 33A and 33B is almost entirelycoated with the shade film 4 f. The shade film 4 f is partially removedto form the light-transmitting pattern 2 e for transferring anintegrated circuit pattern, light-transmitting patterns 2 b and 2 c formarks, and a square light-transmitting pattern 2 f.

[0228] Thereafter, as in the first embodiment, defect inspection isperformed (step 307). If a defect is detected, defect correction isperformed (step 308). If no defect is detected, the cleaning process isperformed (step 309).

[0229] Subsequently, as shown in FIGS. 34A and 34B, a resist film(photosensitive organic film) 3 having a thickness of about 150 nm iscoated on the first major surface of the mask blanks 1 (metal mask)shown in FIGS. 31A and 31B (step 310). When the mask M3 b is reclaimed,the resist film 3 is coated on a metal mask shown in FIGS. 32A and 32B.When the mask M2 c is reclaimed, the resist film 3 is coated on a metalmask shown in FIGS. 33A and 33B. Mask pattern delineation anddevelopment are performed to form the shade pattern 3 a or the shadefilm 3 b constituted by the resist films shown in FIGS. 26A to 26D toFIGS. 28A and 28B, thereby manufacturing the masks M3 a, M3 b, and M3 c(steps 311 and 312).

[0230] Thereafter, the patterns of the masks M3 a, M3 b and M3 c aretransferred onto wafers by using an exposure device (step 313), as inthe first embodiment, and then the patterns on the wafers are subjectedto defect inspection to check the presence/absence of mask defects (step314). The defect inspection for the resist mask is not limited to testexposure as in the first embodiment. A method of inspecting defects ofthe masks M3 a, M3 b, and M3 c without performing exposure may beemployed (the method can be employed in defect inspection for resistmasks (to be described later). If a fatal defect was detected, theresist film (the shade pattern 3 a or the shade film 3 b ) was stripped(step 315), mask defect inspection was performed (step 316), andcleaning was performed (step 317). The shade pattern 3 a, the shade film3 b, or the like constituted by the resist film was delineated again,and development was performed to manufacture the masks M3 a, M3 b, andM3 c again. Thereafter, wafer exposure was performed to perform defectinspection (steps 313 and 314). The masks M3 a, M3 b, and M3 c which hadpassed the defect inspection were used as masks for wafer exposure as inthe first embodiment (step 318). When the masks are wasted, resist strip(step 315), defect inspection (step 316), and cleaning (step 317) wereperformed to returns the states of the mask to the states of the metalmasks shown in FIGS. 31A and 31B to FIGS. 33A and 33B. Thereafter, byusing the metal masks shown in FIGS. 31A and 31B to FIGS. 33A and 33B,masks each having another integrated circuit pattern obtained bycorrecting the design of the integrated circuit pattern or anotherintegrated circuit pattern which is newly designed were produced throughthe resist coating step 310 to the defect inspection step 314 (throughthe resist strip step 310 to the defect inspection step 314 whencorrection was performed).

[0231] The reclaiming steps for returning the states of the resist masks(the masks M3 a, M3 b, and M3 c) to the states of the metal masks willbe described below with reference to FIGS. 35A and 35B to FIGS. 37A to37B. Although the mask M3 a will be mainly illustrated, the sameprocesses as those performed to the mask M3 a are performed to the othermasks M3 b and M3 c.

[0232] The shade pattern 3 a (the shade film 3 b in the mask M3 c)constituted by a resist film was stripped from the exposed mask M3 a bythe same manner as in the first embodiment as shown in FIGS. 35A and35B. The metal shade pattern 4 e is left in the integrated circuitpattern region of the mask M3 a. Subsequently, a cleaning process isperformed to remove particles 50 on the surface of the metal mask as inthe first and second embodiments. In this manner, the mask is reclaimedin the state of the metal mask shown in FIGS. 31A and 31B. Thereafter,as shown in FIGS. 36A and 36B, as in the first embodiment, the resistfilm 3 is coated on the first major surface of the mask blanks 1 (metalmask) shown in FIGS. 31A and 31B to FIGS. 33A to 33B, mask patterndelineation and development are performed to form the shade pattern 3 a(shade film 3 b in the mask M3 c) constituted by a resist film, therebymanufacturing the mask M3 a. In this case, such a case is illustratedthat a shade pattern 3 a having a shape or an arrangement which isdifferent from that of the shade pattern 3 a shown in FIGS. 26A to 26Bis formed. As a matter of course, the same pattern as the shade pattern3 a shown in FIGS. 26A and 26B may be formed. In the description of themethod of manufacturing and reusing a mask, a case in which a shadepattern or a shade film is formed by a single resist film is explained.The methods can also be applied to a case in which the shade portion isconstituted by a laminate film constituted by a photosensitive organicfilm and a photoabsorptive organic film.

[0233] According to this embodiment, in addition to the effects (forexample, the effects (1), (2), (3), and (5)) of the first embodiment,the following effect can be obtained.

[0234] More specifically, only a part of the mask pattern is reclaimed,pattern delineation which occupies the most of the mask cost can beconsiderably reduced. A small number of masks of many types arefrequently used in a system LSI. On the other hand, the system LSIincludes a large number of circuit patterns made into IPs, this effectis specially great. When a wiring layer is partially changed, the effectis specially advantageous.

[0235] (Fourth Embodiment)

[0236] The fourth embodiment describes a modification of the thirdembodiment. The third embodiment illustrates a case in which all shadepatterns in one region in an integrated circuit pattern region of a maskare formed by resist films.

[0237] However, the arrangement of a shade pattern of a resist film on amask is not limited to the arrangement of the third embodiment. Theshade pattern may be arranged like a shade pattern 3 a of a resist filmshown in FIGS. 38A. This mask M4 has a structure in which a metal shadepattern 4 e is connected to the shade pattern 3 a of the resist film tomake it possible to transfer an integrated circuit pattern onto a wafer.Such a mask M4 is effectively used when wiring paths are switched by amanner of arrangement of the shade pattern 3 a of the resist film, forexample, in a change of wiring paths depending on a modification orchange of electric characteristic values in development of asemiconductor integrated circuit device, a change of wiring paths in aredundant circuit configuration.

[0238]FIG. 38B shows a conductive film pattern 8 b (integrated circuitpattern) transferred onto a wafer by the mask M4 in FIG. 38A. FIGS. 38Cshows the state of a metal mask from which the shade pattern 3 a in FIG.38A is removed by performing the reclaiming process. FIG. 38D typicallyshows a conductive film pattern 8 c obtained when a pattern istransferred on to a wafer by using the metal mask in FIG. 38C.

[0239] In the fourth embodiment, in addition to the effects obtained inthe third embodiment, the following effects can also be obtained.

[0240] (1). By a mask reclaiming process, an extremely partialmodification or change in an entire integrated circuit pattern can beeasily performed within a short period of time. Therefore, a period oftime required for manufacturing a mask can be considerably shortened.

[0241] (2). By performing a mask reclaiming process, the cost ofmaterials, the cost of steps, and the cost of fuel can be madeconsiderably smaller than those obtained when a mask is totallymanufactured again from the start in extremely partial change ormodification of the mask.

[0242] (3). By a mask reclaiming process, resources can be effectivelyutilized.

[0243] (Fifth Embodiment)

[0244] In this embodiment, a technique for coating metal shade patternswith protective films in the masks according to the first, third, andfourth embodiments will be described below.

[0245] In the present invention, since the mask is reused as describedabove, the metal shade pattern requires certain resistance. In thisembodiment, the metal shade pattern is covered with a protective film.In this manner, since the metal can be protected in a strip process of ashade pattern of the resist film in the mask or a mask cleaning process,the resistance of the shad pattern made of the metal can be improved.For this reason, since the number of times of reusing of a mask can beincreased, resources can be effectively utilized. In addition, the costof a mask can be further reduced. Chromium which is generally used asthe material of a shade film of a normal mask can also be used as thematerial of a shade film.

[0246]FIG. 39A shows a concrete example of the section of the mask M5 a.FIG. 39A illustrates a case in which a protective film 10 is adhered toonly the upper surface of a shade pattern 4 a. A metal frame (shadepattern 4 a) or the like is preferably a metal frame of an upperprotective type obtained by a sputtering method which generates a smallnumber of defects. The protective film 10 is formed as follows. That is,a shade film is deposited on mask blanks 1 by a sputtering method, theprotective film 10 is deposited on the shade film by a sputtering methodor the like, and the protective film 10 and the shade film arepatterned. FIG. 39B shows a state of a metal mask on a reclamationinitial stage after a shade pattern 3 a of a resist film is removed. Inorder to form a new shade pattern, as in the first embodiment, a resistfilm forming a shade pattern may be coated, a pattern may be delineatedby using an electron beam, an ultraviolet ray, or the like, and adevelopment process may be performed.

[0247]FIG. 40A shows a concrete example of the section of another maskM5 b. FIG. 40A illustrates a case in which a protective film 10 isadhered to the surfaces of shade patterns 4 a and 4 e (i.e., the uppersurfaces and the side surfaces of the shade patterns 4 a and 4 e) andthe first major surface of mask blanks 1. When the fine shade pattern 4e for transferring an integrated circuit pattern is protected, aprotective film of an entire coating type is preferably used. Theprotective film 10 used in this case is formed by, e.g., a CVD method, asputtering method, or the like after the shade patterns 4 a and 4 e arepatterned. A shade pattern 3 a of a resist film is patterned and formedon the protective film 10. FIG. 40B shows a state of a metal mask on areclamation initial stage after the shade pattern 3 a of the resist filmof FIG. 40A is removed. A reclaiming method is the same as thatdescribed above.

[0248] As the protective film 10, for example, a titanium oxide film wasused. In addition, an alumina film may be used. These films have goodresistance to chemicals or oxygen ashing. When the protective film 10was adhered, resistance to oxygen plasma ashing or resistance to ozonesulfuric acid could be remarkably improved, and the number of times ofreclamation which could be performed could be increased. As the materialof the protective film 10, a silicon oxide film can also be used. Thisstructure can also be applied to any masks according to the first,third, and fourth embodiments.

[0249] (Sixth Embodiment)

[0250] This embodiment describes a technique for sharing a configurationby steps in manufacturing a mask, steps in reusing a mask, and steps inmanufacturing a semiconductor integrated circuit device. The embodimentillustrates a case in which a mask and a wafer are processed in the sameclean room. This case will be described below with reference to FIG. 41.

[0251] The flow of a mask will be described below. A resist film forforming a shade pattern is coated on the blanks by a coater, and maskdelineation is performed by delineation device (steps 601 a and 602 a).Subsequently, development is performed, and a produced masks (resistmasks) is stored in a stocker (steps 603 a and 604 a). After the patternof the mask is exposed on a wafer by a scanner (exposure device) (step605), and the presence/absence of a mask defect is decided (step 606 a).If a defect is detected, the shade pattern of the resist film isstripped (step 607 a), and the flow returns to the resist coating stepperformed by the coater to form a shade pattern of a resist film (step601 a). When the mask used in wafer exposure is to be used later, themask is returned to the stocker (step 608 a). When the mast is not to beused later, the shade pattern of the resist film is stripped (step 607a), and the mask is utilized as reclaimed blanks.

[0252] On the other hand, after a process such as a process of forming acoating is performed in a foregoing process (wafer process) (step 601b), a resist film is coated by a coater (step 602 b), and exposure isperformed by the mask with a scanner (step 605). After a resist patternis formed by performing development (step 603 b), and defect inspectionis performed on the wafer to separate a mask defect from a defect causedby a wafer process (step 604 b). When a defect is detected, theinformation is supplied to the mask side. On the mask side, it ischecked whether a defect exists on the mask or not. When the defect isdetected, as described above, the shade pattern of the resist film onthe mask is stripped, and a shade pattern of a resist film is formed(steps 606 a and 607 a and steps 601 a to 604 a). After the defectinspection (step 604 b) on the wafer side, wafer inspection is performedby using length measuring SEM (Scanning Electron Microscope),registration machine, and the like (steps 605 b and 606 b). An etchingusing the resist pattern on the wafer as a mask or a process ofimplanting an impurity is performed, and the resist film is stripped toshift the control flow to the next step (steps 607 b and 608 b).

[0253] In this flow, the scanner is shared in the same clean room, anddefect inspection information or the like is shared through aninformation transmission means such as cable, wireless, or opticalcommunication or a storage medium. Another device is used to strip theresist film. This is because a wafer made of silicon and blanks having amain portion made of quartz glass are different from each other inweight and shape, because a carrier system cannot be easily applied tothe wafer and the blanks, and because the wafer and the blanks haveconsiderably different specific heats.

[0254] According to this embodiment, in addition to the effects obtainedin the first to sixth embodiments, the following effects can beobtained.

[0255] (1). The configuration is shared by the steps in manufacturing amask, the step in reusing a mask, and the steps in manufacturing awafer, so that steps related to each other can be integrally managed.

[0256] (2). Pieces of information obtained in the respective steps canbe effectively utilized in other steps by the above sharing.

[0257] (3). According to the item (2), defect correction or a change indesign can be performed at, e.g., an early stage. For this reason,useless materials and useless steps can be reduced.

[0258] (4). According to the item (1), (2), or (3), manufacturingefficiency of a mask and a semiconductor integrated circuit device canbe made higher than that obtained when the respective steps areindependently managed.

[0259] (5). According to the items (1) to (4), a development period anda manufacturing period of a semiconductor integrated circuit device canbe shortened.

[0260] (6). According to the items (3) and (4), the cost of asemiconductor integrated circuit device can be reduced.

[0261] (Seventh Embodiment)

[0262] In general, mask substrates (or blanks) comprise differentmaterials depending on exposure wavelengths to be used, and the masksubstrates are classified by ranks depending on the degrees of flatnessof the surfaces of the mask substrates. For example, a glass for an ibeam (wavelength of 365 nm) or a KrF excimer laser, a glass for an ArFexcimer laser, and a glass for an F₂ excimer laser contain differentcontents of OH or different processes. The difference exhibits as adifference of irradiation resistances. The types and qualities of theglasses cannot be easily discriminated from each other by simplemeasurement of transmittances or the like, but can be discriminated byexpensive analysis of material composition states or the like.

[0263] It is supposed that a normal mask is reclaimed, a pattern portionmade of chromium is stripped, and glass polishing is performed to returnthe mask to a pure glass plate (mask substrate). For this reason, it isdifficult to decide a wavelength to which the reclaimed mask substratecorresponds. This is because mask information for specifying awavelength or the like is also erased. In addition, the degree offlatness of the mask substrate is important because transfer performanceis dependent on the degree of flatness. However, since the glasspolishing is performed, the state before the reclamation is differentfrom the state after the reclamation, and the degree of flatness must bemeasured again. According to this, the degree of flatness is high beforethe reclamation, but the degree of flatness may be low. Classificationof the degrees of flatness is performed by a selection method, and arate of appearance of mask substrates (blanks) having high degrees offlatness is low. A method of reclaiming a mask has the above problem.

[0264] In this embodiment, a method of solving the above problems isprovided. The embodiment will be described below by using FIG. 42showing a reusing procedure of a mask and FIGS. 43A and 43B and FIGS.44A and 44B showing the structures of blanks.

[0265] The degree of flatness of glass blanks is measured (step 701).Subsequently, for example, pieces of information such as a managementnumber, the degree of flatness, and a suitable exposure wavelength arewritten in a metal frame in place of marks such as a character, a sign,and a bar code (step 702).

[0266]FIGS. 43A is a plan view of blanks, and FIG. 43B is a sectionalview of the blanks. FIGS. 43A and 43B illustrate a case in which amanagement information 11 a, a quality information 11 b such as thedegree of flatness, and a mask information pattern (blanks informationpattern) such as a suitable exposure wavelength information 11 c areexpressed with characters by partially removing the metal frame (shadepattern 4 a). In this case, the case in which pieces of information arewritten in the metal frame (shade pattern 4 a) is illustrated, and ametal pattern is formed in a light-transmitting region on the maskblanks 1, so that these pieces of information may be written.

[0267]FIG. 44A is a plan view of other blanks, FIG. 44B is a sectionalview of the blanks. FIGS. 44A and 44B illustrate blanks which do not usea metal and a case in which the management information 11 a, the qualityinformation 11 b such as the degree of flatness, and the maskinformation pattern such as the suitable exposure wavelength information11 c are formed by partially forming a trench in a peripheral region ofthe second major surface of the mask blanks 1. As the mask informationpattern, a bar code was used. When the trench is formed in the maskblanks 1, it is preferable that the trench is formed in the second majorsurface opposing the pattern surface (first major surface) becauseuneven coating or the like of a resist film for forming a shade patternis not easily generated. However, the trench must not be formed in theabsorptive surface of an exposure device. In FIGS. 44A and 44B, althoughboth a trench expression and a metal print are used, one of them may beused.

[0268] After the step of forming a discrimination mark, a resist filmfor forming a shade pattern (step 703), and a mask pattern is delineated(step 704). Development is performed to form a shade pattern constitutedby a resist film on the blanks (step 705), thereby manufacturing a mask(resist mask). Subsequently, as in the first embodiment, defectinspection is performed by wafer exposure using the mask (steps 706 and707), and wafer exposure is performed (step 708). Shade patternsconstituted by resist films are removed from mask which does not passthe defect inspection and a mask which is wasted in wafer exposure, themasks are subjected to cleaning and particle check (steps 709 to 711),classified by applications and grades on the basis of the maskinformation patterns described above, and stored and managed (step 712).Reclaimed blanks depending on an application or a necessary grade areout of the stocker, and a reclaimed mask (resist mask) is produced againfrom the step of coating a resist film (step 703) according to theprocedure.

[0269] According to this embodiment, in addition to the effects obtainedin the first to sixth embodiments, the following effects can beobtained.

[0270] More specifically, since a structure in which mask information isnot removed in the reclaiming step is employed, reproduced blankscorresponding to an application and quality can be efficiently supplied.In this reclaiming step, polishing is not used, the degree of flatnessof the blanks is not changed. The information of the degree of flatnessin production can be used from a management number or the like, thedegree of flatness may not be necessarily measured again. For thisreason, blanks having high quality can be extremely easily providedwithin a short period of time. More specifically, the blanks can berepeatedly used without newly obtaining high-quality blanks having thehigh degree of flatness. When the mask information such as a managementnumber or the like, a specific reclaimed blanks can be supplied to aspecific company. When the mask information such as a managementinformation, information inherent in blanks such as a reticle alignmentarrangement accuracy or a flatness in-surface distribution can bepreferably managed.

[0271] (Eighth Embodiment)

[0272] In the eighth embodiment, a case in which the spirit and scope ofthe present invention is applied to a method of manufacturing asemiconductor integrated circuit device having a CMIS (complementaryMIS) circuit of, e.g., a twin well system will be described below.

[0273]FIG. 45 is a sectional view of a main part of a wafer 6 in thesteps in manufacturing the semiconductor integrated circuit device. Thewafer 6 is constituted by a semiconductor thin plate having, e.g., aflat circular shape. A semiconductor substrate 6 s constituting thewafer 6 comprises, e.g., an n⁻-type silicone (Si) monocrystal, and, forexample, an n-type well NWL and a p-type well PWL are formed on theupper side of the semiconductor substrate 6 s. For example, phosphorousor arsenic (As) are implanted in the n-type well NWL. For example, boronis implanted in the p-type well PWL.

[0274] On a major surface of the semiconductor substrate 6 s, a fieldinsulating film 12, constituted by, e.g., a silicon oxide film, forisolation is formed by a LOCOS (Local Oxidization of Silicon) method orthe like. An isolation portion may be a trench. More specifically, aninsulating film may be buried in a trench formed in the semiconductorsubstrate 6 s in the direction of the thickness to form the isolationportion. In an activation region surrounded by the field insulating film12, an NMIS Qn and a pMIS Qp are formed.

[0275] Gate insulating films 13 of the nMIS Qn and the pMIS Qp areconstituted by, e.g., silicon oxide films and formed by a thermaloxidation method or the like. Gate electrodes 14 of the nMIS Qn and thepMIS Qp are formed such that, after a conductive film, made of, e.g.,low-resistance polysilicon, for forming a gate is deposited on a majorsurface of the wafer 6 by a CVD method or the like, the film ispatterned and processed by a photolithography technique and a normaletching technique using the mask. Although the gate length is notlimited to a specific value, the gate length is, e.g., about 0.15 μm.

[0276] A semiconductor region 15 for forming a source or a drain of thenMIS Qn is formed to be self-aligned to the gate electrodes 14 suchthat, e.g., phosphorous or arsenic is implanted in the semiconductorsubstrate 6 s by an ion injection method or the like by using the gateelectrode 14 as a mask. In addition, a semiconductor region 16 forforming a source or a drain of the pMIS Qp is formed to be self-alignedto the gate electrodes 14 such that, e.g., boron is implanted in thesemiconductor substrate 6 s by an ion injection method or the like byusing the gate electrode 14 as a mask.

[0277] The gate electrode 14 is not necessarily constituted by a singlefilm made of low-resistance polysilicon, and can be variably changed.The gate electrode 14 may employ a so-called polyside structure in whicha silicide layer made of a tungsten silicide or cobalt silicide isformed on, e.g., a low-resistance polysilicon layer or may employ aso-called poly-metal structure in which a metal film made of tungsten orthe like is formed on, e.g., a low-resistance polysilicon film through abarrier conductive film made of titanium nitride or tungsten nitride.

[0278] On the semiconductor substrate 6 s, as shown in FIG. 46, aninsulating interlayer 17 a constituted by, e.g., a silicon oxide film isdeposited by a CVD method or the like, and a polysilicon film isdeposited on the upper surface of the insulating interlayer 17 a by aCVD method or the like. Subsequently, the polysilicon film is patternedby a photolithography technique and etching by using a mask, and animpurity is implanted in a predetermined region of the patternedpolysilicon film, so that a wiring 18L and a resistor 18R constituted bya polysilicon film.

[0279] Thereafter, as shown in FIG. 47, an HLD film 17 b constituted by,e.g., a silicon oxide film is deposited on the semiconductor substrate 6s, a contact hole 19 for partially exposing semiconductor regions 15 and16 and the wiring 18L is formed in the insulating interlayer 17 a andthe HLD film 17 b by a photolithography technique and etching using themask. In addition, metal films made of, e.g., titanium (Ti), titaniumnitride (TiN), and tungsten (W) are sequentially are deposited on thesemiconductor substrate 6 s by a sputtering method, a CVD method, andthe like, and a resist pattern is formed on the metal films byphotolithography using the mask. The resist pattern is etched to form afirst wiring layer 20L as shown in FIG. 48. Thereafter, a second wiringlayer and the subsequent wiring layers are formed like the first wiringlayer 20L to manufacture a semiconductor integrated circuit device.

[0280] For example, in a custom LSI product, in particular, mask debug(including correction or change of a mask) is frequently performed aboutthe first wiring layer. In the mask debug, the mask is wasted by onlyslightly performing wafer exposure, and the number of masks required tomanufacture one product. For this reason, the spirit and scope of thepresent invention are applied to the step, the great effect of reducingthe cost can be achieved.

[0281] (Ninth Embodiment)

[0282] This invention relates to a flow of a mask between companies anda method of determining a fee. FIG. 49 shows an example of an outline ofthe flow of a mask according to this embodiment. The embodiment will bedescribed below with reference to FIG. 49. As blanks used in theembodiment, the blanks shown in FIGS. 8A and 8B, FIGS. 9A and 9B, FIGS.10A and 10B, and FIGS. 21A and 21B. A shade pattern and a shade film areabbreviated as shade portions.

[0283] Company A (blanks supplier) is a company for supplying blanks,and is a blanks maker or a blanks reclamation. Company A supplies blankshaving quality according to a request of a user to a the user, andrecovers blanks to be reclaimed. Company B and company C (mask user) areIC foundries or IC chip makers having mask shops in their factories.Company D and company E (mask user) are mask makers, and company F andcompany G (mask user) are IC chip makers which do not have mask shops intheir factories. However, the flow of a mask is essential, and therespective companies are only examples. For example, the number ofcompanies is not regulated to the number. The number of IC companies maybe increased by adding company H and company I. Company F and company Gmay be IC foundries. Although a product used in this embodiment isexpressed as an IC (Integrated Circuit), the IC is an example whichrepresents not only a semiconductor IC using silicon or gallium arsenide(GaAs) as a substrate, but also various products such as a TFT panel anda liquid crystal panel.

[0284] Company A acquires blanks having a mark indicating a grade suchas the degree of flatness and a management number which are formed bythe method described in the seventh embodiment or produces the blanks inthe company to store and manage the blanks. In this case, if a user hasa request, the management number may be omitted. In order to immediatelyrespond to immediate delivery required by the user, the blanks arepreferably classified by grades to be stocked and managed.

[0285] A user (companies B to E in this case) orders company A to shipblanks. The blanks delivered to company B is subject to resist coating,mask delineation, development, wafer exposure, and defect inspection bythe methods described in the first and second embodiments. When the maskdoes not pass the defect inspection, the shade portion constituted bythe resist film on the mask is stripped in company B, and the mask isrecovered by company A. When the blanks pass the defect inspection, themask is used in wafer exposure. When the mask is wasted, the shadeportion constituted by the resist film on the mask is stripped. When theshade portion constituted by the resist film on the mask is stripped inthe company, secret items such as pattern data may not leak out of thecompany. In the foundry, since customer information must not leak, it isimportant that the customer information is prevented from leaking.

[0286] Also in company C, although a mask is produced in the same stepsdescribed above and used, a mask which does not pass defect inspectionand a mask which is wasted in wafer exposure are recovered by company Awithout stripping the shade portions of the resist film from the masks.

[0287] Blanks delivered to company D are subjected to coating of aresist film, defect inspection, mask delineation, and development, andare shipped to the IC maker of company F or company G as a mask. Whenthe blanks which do not pass defect inspection, the shade portionconstituted by the resist film is stripped, and the blanks are deliveredto company A. Company F performs wafer exposure by using the mask, anddefect inspection of the pattern on the wafer to decide thepresence/absence of a mast defect. When the blanks pass the defectinspection, the blanks are used in wafer exposure. When the blanks donot pass defect inspection, and when the blanks are wasted, the blanksare returned to company D. In company D, the shade portion constitutedby the resist film is stripped, the blanks are sent to company A. Alsoin company G, as in company F, wafer exposure is performed by using themask, and the pattern on the wafer is subjected to defect inspection todecide the presence/absence of a mask defect. In company G, however,unlike in company F, when the blanks do not pass defect inspection andare wasted, the blanks is returned to company A.

[0288] On the mask which is returned to company A, when a shade portionconstituted by a resist film is adhered, the resist film is strippedfirst, and cleaning is performed. When the resist film has beenstripped, cleaning is performed. Thereafter, particle check isperformed. The passing criterion of particle check is that the number ofparticles each having a reference size or larger is a reference numberor larger. In this case, the particles include not only an adhesiveparticle and a nick defect such as a scratch. When a particle is left,cleaning and particle check are performed again. A mask which does notpass the particle check even though the mask is subjected to cleaningtimes the number of which is equal to or larger than a reference numberis casted away. Masks which pass the particle check are classified bygrades such as the degrees of flatness and suitable wavelengths on thebasis of grade marks and management numbers. A transmittance to light ofa suitable wavelength is measured as needed. The mask blanks areclassified by the grades and stocked. According to a request of a user,blanks of a grade corresponding to the request are shipped as reclaimedblanks. The classification means that the blanks are classified intogroups and managed. The blanks are not always stocked at one position. Arequest for blanks, a request to reclaim a mask, or the like can beperformed such that a person in each company or each section accesses ahomepage prepared by company A or the like or a communication areathrough a communication line such as an Internet line or a lease line.As a matter of course, the request can also be performed by a telephoneline, another communication means, or the like. In this manner,manufacturing masks and circulation of reclamation can be efficientlyperformed. Company A can widely and immediately supply informationrelated to reclamation of blanks and masks. The above example describesthe case in which test exposure is performed in defect inspection of aresist mask. However, the defect inspection of the resist mask, as inthe first embodiment, is not limited to defect inspection using testexposure. A method of inspecting a defect of a mask without performingexposure may also be employed.

[0289] In the above flow of a mask, a fee for the transaction betweencompany A and company B is defined as follows, for example.

[0290] Company B changes the prices of the blanks which are delivered tocompany A depending on the number of blanks which are shipped fromcompany A to company B, or the prices of blanks to be shipped arechanged according to a ratio of the number of blanks delivered tocompany A by company B to the number of blanks shipped from company A tocompany B, i.e., a recovery. In addition, company A changes the price ofrecovery blanks according to the grade of the degree of flatness and asuitable wavelength. In this manner, the recovery of the blanksincreases. Therefore, since a recycling rate also increases, the cost ofthe blanks decreases. This effect is specially great in blanks having ahigh grade. Company A can obtain profits through a blanks reclamationbusiness and a blanks management business. Company B can advantageouslyreduce costs by utilizing wasted blanks. This relationship is similarlysatisfied between company A and company C and between company A andcompany D. In addition, since this recycle system advances saving ofresources, the invention is effective in social environment.

[0291] Company A also receives blanks having a grade display from acompany such as company G to which company A does not directly shipblanks at prices depending on the grade (degree of flatness and suitablewavelength). Company A can easily obtain profits because the procurementcost is reasonable. In addition, company A receives blanks having amanagement number of company A at a price which is higher than the priceof blanks having a management number of another company for thefollowing reasons. That is, blanks which are not own must be subjectedto the step of adding a serial number or the like to increase the cost.In addition, a company prevents blanks of the company from beingdelivered to another blanks reclamation to prevent a recovery fromdecreasing. When the recovery decreases, a rate of new blanks becomeshigh, and company A must pay high costs.

[0292] According to this embodiment, manufacturing of masks, reclamationof the masks, and manufacturing of products using the masks can beefficiently associated with each other. Resources can be effectivelyutilized. Therefore, improvement in economy and industry can beadvanced.

[0293] The invention made by the present inventor has been describedabove on the basis of the embodiments. The present invention is notlimited to the embodiments described above, and various changes andmodifications of the invention can be effected without departing fromthe spirit and scope of the invention.

[0294] For example, in the ninth embodiment, company A can supply blankson which a resist film for forming a shade portion is coated torespective companies. In this case, each of the companies maymanufacture or reclaim a mask from the step subsequent to the step ofcoating a resist film.

[0295] In the ninth embodiment, after company F or company G removes ashade pattern constituted by a resist film from a mask, the company mayreturn the resultant blanks to company D or company A.

[0296] In the above description, the invention made by the presentinventor is applied to a method of manufacturing a semiconductorintegrated circuit device having a CMIS circuit in an application fieldserving as the background of the invention. The present invention is notonly the semiconductor integrated circuit device, but also asemiconductor integrated circuit device having a memory circuit such asa DRAM (Dynamic Random Access Memory), an SRAM (Static Random AccessMemory), or a flush memory (EEPROM: Electric Erasable Programmable ReadOnly Memory), a semiconductor integrated circuit device having a logicalcircuit such as a microprocessor, and an embedded semiconductorintegrated circuit device in which the memory circuit and the logicalcircuit are formed on the same semiconductor substrate. In addition, thepresent invention can effectively applied to a photolithographytechnique used in manufacturing, e.g., a semiconductor device, asuper-conductive device, a micromachine, a magnetic head, an electronicdevice, a liquid crystal panel, and the like.

[0297] Effects obtained by a typical invention disclosed by the presentapplication will be described below.

[0298] (1). According to the present invention, after a shade patternconstituted by a resist film formed on a mask is stripped, and a newshade pattern constituted by a resist film is formed on the mask toreclaim the mask, so that the mask can be reused.

[0299] (2). According to the item (1), the cost of a mask can bereduced.

[0300] (3). According to the item (1), the present invention iseffective in saving of resources and a countermeasure againstdestruction of the environment.

What is claimed is:
 1. A method of reclaiming a photomask comprising thesteps of: (a) patterning and forming a first shade portion constitutedby a resist film on a mask substrate to manufacture a photomask; (b)performing an exposure process by using the photomask to transfer adesired pattern onto a substrate to be processed; (c) stripping thefirst shade portion constituted by the resist film; and (d) patterningand forming a second shade portion constituted by a resist film on themask substrate from which the first shade portion constituted by theresist film is stripped to reclaim the photomask.
 2. A method ofreclaiming a photomask comprising the steps of: (a) preparing a masksubstrate having a shade portion made of a metal in a peripheral regionaround an integrating circuit pattern region; (b) patterning and forminga first shade portion constituted by a resist film in the integratingcircuit pattern region to manufacture a photomask on a mask substratehaving the shade portion made of the metal; (c) performing an exposureprocess by using the photomask to transfer a desired pattern onto asubstrate to be processed; (d) stripping the first shade portionconstituted by the resist film on the photomask to remanufacture a masksubstrate having the metal shade portion; and (e) patterning and forminga second shade portion constituted by a resist film in the integratedcircuit pattern on the mask substrate having the shade portion made ofthe metal to reclaim a photomask.
 3. A method of reclaiming a photomaskcomprising the steps of: (a) preparing a mask substrate having a firstshade portion made of a metal formed in an integrated circuit patternand a second shade portion made of a metal formed in a peripheral regionaround the integrating circuit pattern region; (b) patterning andforming a first shade portion constituted by a resist film in theintegrating circuit pattern region to manufacture a photomask on a masksubstrate having the first and second shade portions made of the metals;(c) performing an exposure process by using the photomask to transfer adesired pattern onto a substrate to be processed; (d) stripping thefirst shade portion constituted by the resist film on the photomask toremanufacture a mask substrate having the first and second metal shadeportions; and (e) patterning and forming a second shade portionconstituted by a resist film in the integrated circuit pattern on themask substrate having the shade portion made of the metal to reclaim aphotomask.
 4. A method of reclaiming a photomask according to claim 2,wherein in the previous step of stripping the first shade portionconstituted by the resist film, a protective film is formed on the shadeportion made of the metal.
 5. A method of reclaiming photomask blanksaccording to claim 2, wherein the shade portion made of the metalcomprises a refractory metal, a nitride of a refractory metal, asilicide of a refractory metal, or a laminate film comprising thereof.6. A method of reclaiming a photomask according to claim 1, furthercomprising the step of: forming a mask information pattern on the masksubstrate.
 7. A method of reclaiming a photomask comprising the stepsof: (a) causing a mask user which uses a photomask to place an orderwith a blanks supplier for supplying photomask blanks for photomaskblanks; (b) causing the mask user to manufacture a photomask having ashade pattern constituted by a resist film in an integrated circuitpattern region by the delivered photomask blanks; (c) causing the maskuser to perform an exposure process by using the photomask; and (d)causing the mask user to strip the shade pattern constituted by theresist film from the photomask subjected to the exposure process and tosell the photomask blanks from which the resist is stripped to theblanks supplier so as to reclaim the photomask blanks as photomaskblanks which can be used again.
 8. A method of reclaiming a photomaskcomprising the steps of: (a) causing a mask user which uses a photomaskto place an order with a blanks supplier for supplying photomask blanksfor photomask blanks; (b) causing the mask user to manufacture aphotomask having a shade pattern constituted by a resist film in anintegrated circuit pattern region by the delivered photomask blanks; (c)causing the mask user to perform an exposure process by using thephotomask; and (d) causing the mask user to sell the photomask subjectedto the exposure process to the blanks supplier so as to reclaim thephotomask as a photomask which can be used again.
 9. A method ofreclaiming a photomask comprising the steps of: (a) causing a photomaskmaker to place an order with a blanks supplier for supplying photomaskblanks for photomask blanks; (b) causing the photomask maker tomanufacture a photomask having a shade pattern constituted by a resistfilm in an integrated circuit pattern region by the delivered photomaskblanks; (c) causing the photomask maker to sell the photomask to adevice maker for manufacturing a predetermined device; (d) causing aphotomask maker to receive a photomask subjected to an exposure processfrom the device maker; and (e) causing a photomask maker to strip theshade pattern constituted by the resist film of the photomask subjectedto the exposure process and received from the device maker and to sellthe photomask blanks obtained in this manner to the blanks supplier soas to reclaim the photomask blanks as photomask blanks which can be usedagain.
 10. A method of reclaiming a photomask comprising the steps of:(a) causing a photomask maker to place an order with a blanks supplierfor supplying photomask blanks for photomask blanks; (b) causing thephotomask maker to manufacture a photomask having a shade patternconstituted by a resist film in an integrated circuit pattern region bythe delivered photomask blanks; (c) causing the photomask maker to sellthe photomask to a device maker for manufacturing a predetermineddevice; (d) causing a photomask maker to receive a photomask subjectedto an exposure process from the device maker; and (e) causing aphotomask maker to sell the photomask subjected to the exposure processand received by the device maker so as to reclaim the photomask as aphotomask which can be used again.
 11. A method of reclaiming aphotomask comprising the steps of: (a) causing a blanks supplier forsupplying photomask blanks to sell photomask blanks for manufacturing aphotomask having a shade pattern constituted by a resist film to aphotomask user which uses a photomask; and (b) causing the blankssupplier to recover the photomask subjected to an exposure process fromthe photomask user, to strip the shade pattern constituted by the resistfilm, and to reclaim the photomask blanks.
 12. A method of reclaiming aphotomask comprising the steps of: (a) causing a blanks supplier forsupplying photomask blanks to sell photomask blanks for manufacturing aphotomask having a shade pattern constituted by a resist film to aphotomask maker which manufactures a photomask; and (b) causing theblanks supplier to recover the photomask subjected to an exposureprocess from a photomask user, to strip the shade pattern constituted bythe resist film, and to reclaim the photomask blanks.
 13. A method ofreclaiming a photomask comprising the steps of: (a) causing a blankssupplier for supplying photomask blanks to sell photomask blanks formanufacturing a photomask having a shade pattern constituted by a resistfilm to a photomask maker which manufactures a photomask; and (b)causing the blanks supplier to recover the photomask from which theshade pattern constituted by the resist film is stripped from aphotomask user and to perform cleaning for removing a particle and aprocess of checking a particle and a scratch to reclaim the photomaskblanks.
 14. A method of reclaiming a photomask comprising the steps of:(a) causing a blanks supplier for supplying photomask blanks to sellphotomask blanks for manufacturing a photomask having a shade patternconstituted by a resist film to a photomask maker which manufactures aphotomask; and b) causing the blanks supplier to recover the photomasksubjected to an exposure process from the photomask maker, to strip theshade pattern constituted by the resist film, and to reclaim thephotomask blanks.
 15. A method of reclaiming a photomask according toclaim 11, wherein the blanks supplier manages the quality of thephotomask blanks on the basis of a blanks information pattern formed inthe photomask blanks.
 16. A method of reclaiming a photomask accordingto claim 11, wherein the blanks supplier changes the transaction priceof photomask blanks recovered from the mask user by the blanks supplieraccording to the number of photomask blanks shipped to the mask user.17. A method of reclaiming a photomask according to claim 11, whereinthe blanks supplier changes the price of photomask blanks according to aratio of the number of photomask blanks recovered from the mask user bythe blanks supplier to the number of photomask blanks shipped to themask user.
 18. A method of reclaiming a photomask according to claim 14,wherein the blanks supplier changes the transaction price of photomaskblanks recovered from the mask maker by the blanks supplier according tothe number of photomask blanks shipped to the mask maker.
 19. A methodof reclaiming a photomask according to claim 14, wherein the blankssupplier changes the price of photomask blanks according to a ratio ofthe number of photomask blanks recovered from the mask maker by theblanks supplier to the number of photomask blanks shipped to the maskmaker.
 20. A method of reclaiming a photomask according to claim 11,wherein the price of photomask blanks recovered or shipped by the blankssupplier is changed according to a quality level described in thephotomask blanks.